Thank you for posting how to downgrade! For others the quick link is: https://help.evernote.com/hc/en-us/articles/360052560314-Install-an-older-version-of-Evernote
For me the new Evernote Mac lacks two critical productivity features I rely on many times daily:
global shortcut keys to create new notes (https://help.evernote.com/hc/en-us/articles/208313358-Keyboard-shortcuts-in-Evernote-for-Mac)
quick notes under Evernote Helper in the toolbar
Hope Evernote re-adds these features in future updates (or keeps the Evernote Legacy version around for a very long time)