agsteele

I don't think it is possible. Sorry.

None of your existing notes will be lost if you drop to Free.  But if you already have more than 50 or more than one notebook you will not be able create any more.  You can edit, export, delete and merge existing notes within the general Free limitations.  So effectively dropping to Free will change your account into an archive.  You could open a second Free account and use that up to the 50 note limit.  I think you could also share notes from your existing, now Free, account without affecting your 50 note limit.  You'll have to try that and see.
As for the price rise, I doubt that there is any reason to think that a price rise next year will be of the order that has been experienced this year following the takeover.  My view is that this is a reset of the prices to take account of around seven years without any increases. Next year probably in line with inflation.

The first option would, I think, be to reinstall.
Use a program called Revo Uninstaller to uninstall. This will fully clean out all corrupted data and program files. The standard Windows uninstall is less complete.
Then reboot your PC and download the installer from evernote.com/download
Reinstall and see if that fixes things for you. You will need to wait a day or so for the data to fully sync.
It looks like you will have to delete the previously deleted stuff manually. You can highlight up to 100 notes are a time. Whilst you are waiting for the app to resync you could do the deletions from the web client.

Go to the web clipper settings and either disable keyboard shortcuts or change the CMD+C option.

I would go to settings in your iPad app.  Choose More Settings which will take you into your account settings. Choose security settings and you'll be asked for a password and then a Google 2FA code.  But there is also and option 'I need help getting a verification code'. You may find a solution there. There is still an option for a text message and that worked for me.
Once you are i the Security Settings area you can manage 2FA and that's where you recover the backup codes.  There's also an option to contact support.

Best off to use Revo Uninstaller to get rid of the old version, if that is what you want. Then reinstall from the latest download from evernote.com
10.63.2 is the latest release.

The new mobile apps include a link to contact support but, of course, the unsupported apps do not.
The website has a support option - https://help.evernote.com/hc/en-us/requests/new?guest=true
You can try out v10 via the web browser interface if you ensure you choose to use v10. The browser is broadly similar to the desktop app minutes a few functions.
The new mobile apps work on devices with at least Android 9. So I'm not sure you will be able to upgrade on your Kindle.

You could try https://help.evernote.com/hc/en-us/requests/new?guest=true and select the Account option

Nothing. The same result in the sort on Android.
If it's an issue for you then you should open a support ticket.

I think that may be the thread that was accidentally deleted by another user which had apologised for his/her error 

Before doing that I'd check the note in the web client. It is conceivable that the local version of the PDF only is damaged. Check that the PDF sync has happened.
Assuming you are on a paid subscription you have the note history running and could open an early copy of the note which should contain the earlier PDF too.

I apologise for not understanding the issue. You sign up for a free service with a limit. You reach that limit and then expect to be able to step around the limit. The reset is achieved by subscribing for the next level up or waiting until the month is over. I'm not sure why you would expect anything else.

Evernote v10 below 10.60 is now unsupported on the desktop and in the process of being withdrawn. If you decline the upgrade you will, soon, find Evernote unavailable for you. 
If the latest version really won't work then you should urgently open a support ticket and ask what they can do to assist. If you have a Free account then you'll need to pay for support. Otherwise make an urgent plan to move on.

Sorry. No.

No there isn't a sort by size available. However, no notes are lost when you downgrade. Notes that exceed the Free account size limit are effectively locked so you cannot edit them but you can view them, print them and, I think, export them. You are restricted by the Free account limits on note size and data transfer but otherwise your existing notes will be unaffected.

It sounds like you might be better moving the rest of the family to a free plan. Of course that will depend on how much data they use and the number of devices. If they can be content with the web client when they are on desktops or tablets and mobile for phones then they might be able to work happily on a free plan. That would certainly give you a more economical solution.
Otherwise, you can advocate for a Family plan but I doubt it will be along anytime soon. I'd suggest you also give your feedback to feedback@evernote.com as well as here.
Good luck with your request.

10 61.10 has behind the scenes stuff to enable AI Search when it is enabled on your account.

After the database has synchronised all the attachments are also stored locally but not labelled as, for example, attachment.pdf Rather they are stored with a unique long character string and without any file suffix. They are present outside the app but not obviously so...

Had auto filing become enabled?
https://www.evernote.com/PersonalSettings.action

Actually 60 versions since 6.25 was replaced. For most of that time 6.25 continued to work with the warning that no future fixes would be available. Shortly all versions before 10.40 will also be deprecated and unsupported.

Third party sites are the only option. Evernote doesn't publish old versions.

Free use comes with limitations. One is that you don't have access to note history. The other is that you have to pay for technical support. If you pay for one month's subscription you will gain access to both. Remember to cancel the subscription after a couple of weeks to ensure that it doesn't renew if you want to drop back to Free.

Ctrl+Alt+1 should open all notes then make your search.
I use Auto Hot Key to automate lots of this type of double shortcut requirement.
 

https://help.evernote.com/hc/en-us/requests/new

Have you had the update to v10 53.1? It arrived with me today. Perhaps this will fix things.