Well I was using Evernote in a legitimate way offered by the company.
All my notes are text-only and I don't need Evernote for anything else. All I need is plain text to keep some info here and there. Out of my 300 notes I'm only actively using about 15.
Even the earlier payment plans were too high for my modest needs (in my view, of course) - plus I didn't need any paid features anyway.
Now my access to the existing notes got basically BLOCKED without any prior warnings or notifications (it's blocked by the payment/trial screen). That is I can't even view them.
Now, I just received a reply from Evernote support. It mentions that "any Free user who currently has more than fifty notes and one notebook will still be able to view, edit, export, share, and delete existing notes and notebooks."
Following their troubleshooting steps, it appears that I at least can now access my notes via the app on my Mac. However, any attempt to log in to Evernote via a browser on another Mac blocks access to notes everywhere, including the app (and logging in via browser is never possible - it's always blocked). Clear as mud? It took me about an hour of various attempts to reach this conclusion.
Hopefully, I'll get a solution from Evernote support to at least view my existing notes reliably on supported devices.