PinkElephant

The points programs have long been discontinued.
You need to contact EN support to be able to use points. It means to cancel your current subscription. Then you need to wait until it expires by itself. Support can then use your points to set up the subscription again. Once the points are consumed, you need to let it expire again. And then you subscribe again, using one of the normal payment methods.
I know, because this was how my points were finally used up, 3 years ago. I am not sure whether it still works like this today. But support can tell.

Probably your local database is corrupted. Try this:
Go to File > Sign Out [name] from the menu bar. Select the "Remove my Evernote data from this device" option, then click Sign out. Restart your computer. Sign back in to Evernote, keep the app open while it downloads your notes from the server  

By default EN will show pdf in single page view (large pdfs as attachment).
Click on the pdf, click on the little menu that appears on the top (desktop), and select all pages view. Or while hovering over the pdf, look out for arrows that appear at the bottom, to switch pages.
If this does not solve your issue, come back and use more words to tell how you create the pdf, how you import it and why you think it has only one page. We like to read some good yarn …

iOS got quite aggressive on preserving battery level, cutting off apps that try to perform in the background.
This means syncing is axed by the OS shortly after locking up an iOS device. There is AFAIK no way around it - you need to keep the app active and the device unlocked until syncing is done.

From my experience the app tries to reach the server right when I open the EN app on my iOS devices. Usually new notes appear in a matter of seconds, from my feeling maybe a little faster in the notes list view than in the Home dashboard view. 
Instead of going to the sync now option in settings, you can go as well to the notes list, pull it down a little with a finger and let go. If there is anything to sync, a syncing wheel indicator will show, and the notes load.
You can check in the app settings in iOS settings whether background sync is active. If your network is on the shaky side, you can as well switch mobile data on. Even with background sync, iOS will not allow major syncing, because it tries to hold battery use down. So a short moment after opening the app remains to download new content from the server.

Try Revo Uninstaller, from the web. When it works, remove everything. Then restart the PC, download from the EN website, install and log in. Once it is open, wait for the initial download to finish before using the client.

Open your account settings, go to personal settings, and disable automatic filing for emails.

Free users can only activate the SMS version.
Authenticator use is a subscribers feature. I use Authy as well, works fine.

.... just think about when uploading any pictures of handwriting, that it must be JPG, PNG or GIF. EN will OCR handwriting only when saved as pictures (this means you have a bunch of them in a note, each one a single page).
It will not OCR handwriting when uploaded as a pdf.

Did you really contact support ?
How did you try to reach them. Have you ever received a return mail with a ticket number ?
What is your method of payment ? Credit card, or one of the stores like iTunes or PlayStore ? 

You are running a pretty aged version (probably of the Windows client).
Probably the best method in this case would be to go to the EN website and download the new client. Since there may be different installation situations, you should read this help document first:
https://help.evernote.com/hc/en-us/articles/360061882314
If then in doubt, contact support.

Make sure you are updated to the latest version of EN from the AppStore.
Then quit the app and restart it. Did the job for me.
If this is not enough, restart the iPad once by completely shutting it down.

Yes, if you proceed with the duplicate, it starts with note history set to zero. From there it will build its own history.
Sometimes good to know: It is a simple way to get rid of all the older versions while keeping the content.
Just try it yourself !

OK, the subscription takes the device limit of the free account out of the equation. Probably your local database is damaged.
I think your best option is to uninstall completely. To do this, get an uninstaller app - the Windows own uninstaller won‘t do the job on this. For Windows the Revo Uninstaller gets good feedback in the forum.
Quit EN, run the uninstaller, make sure to select all elements, confirm. Then restart the PC and reinstall fresh from the EN website. Log in, and now wait until the initial install has finished.
There will be a new version EN 10.39 for PC and Mac releasing today (at least it is announced). It has a relevant bug fix, so maybe make sure you get this newest release. Or use 10.38, and make sure to update once the new version is there.

On a subscription, or on Free ?
Saving own templates is a subscription feature.

EN uses the dictionary installed on your Mac for all apps. The file is called "LocalDictionary" and can be edited with any text editor. Just open it, find the word and delete it. Save the file.
You find the file here:
/Users/myuser/Library/Spelling

This help article should answer your questions:
https://help.evernote.com/hc/en-us/articles/209005157

Probably your local database is creating the problem. It will not be replaced, even not by an uninstall, because the Mac treats it (correctly) as data, which will not be removed by an uninstall.
Option 1: Get the app AppCleaner from the web, install it and run it to uninstall. When the list of components appears, check all of them to remove every part of the install. Then (to be safe) restart the Mac, and reinstall the EN client.
Option 2: Log out of your account, then quit the app (really shut it down, not only closing it), then remove the „Evernote“ folder here: 
~/Library/Application Support/
Restart the app, log in. Should do now.
In both cases I t needs to download your data again from the EN server. Content for offline use will only be available after a while, maybe several days if on a slow internet.

Nothing is random - you have an account setting enabled that tells EN to guess the notebook.
Go to account, personal settings and disable the „smart filing“ feature. It is the first setting under the language settings.

Personally I doubt Apple Script will work. Think of EN v10 being a browser, with the app as front end.
The information is enclosed in the browser, not in the OS level. And AFAIK the framework used is not scriptable.
But wish you success - could open the door for other scripting as well.

… or use an app like AppCleaner to uninstall. The Macs own Uninstaller will not remove data files.

Yes, that describes the implementation. You can clip and view. Once you want to edit anything, you need to simplify.
When this was introduced with v10, there were a few discussions about this approach. Since then little forum traffic about it.
In my post above I have described how you can reach EN. I doubt this will be changed - I think it was a deliberate decision to allow editing only on code created by the simplifying action inside of EN.

How old is your iPhone ?
Has it ever gotten a new battery ?
What you describe is typical for a battery powered device running low on power. Old batteries drop off in voltage supplied to the CPU. And the clock speed (= computing power) of the CPU is a direct function of the voltage on which it is running.
Go to a Genius Bar or an authorized Apple service, and have the battery checked.
If it is at 80% or below, let them replace it. You will get a „new“ phone for 49 $, and apps stop crashing.
https://support.apple.com/iphone/repair/service/battery-power
P.S. The same can happen when a phone has a damaged battery cell, for example through bending it accidentally. Can for example happen by sitting down with the phone in a rear pocket.

Or solve the problem at the root and merge the two accounts into one:
https://help.evernote.com/hc/en-us/articles/209004867

This page shows the latest software for the S1500 scanner:
https://www.fujitsu.com/global/support/products/computing/peripheral/scanners/scansnap/software/s1500.html
You find a note at the bottom of the table that the auto-update does not work for this scanner !