I am a Premium member running EN v7.14 under MacOS Catalina 10.15.2 on my new 2019 16" Macbook Pro (16 GB RAM) and a late 2015 iMac (3.1 GHz i5, 16 GB RAM). EN runs awesomely on the MBP - fast searching, new notes are quickly created via copying & pasting. Not so on the iMac. I didn't realize how unresponsive EN was using the iMac until I got the new MBP.
As a possible fix, I recently recreated the full text search index from the Troubleshooting menu under Help. I let EN run for 3 full days until the %CPU usage dropped. Searches are much faster now so that worked well. However, still get the spinning beach ball a lot. If I have added new notes on another device (e.g, MBP, iPhone, or iPad), syncing with the EN cloud is the slowest of all devices.
Am I candidate to use the free AppCleaner application to uninstall Evernote, and then reinstall it? My database contains ~28,000 notes.