2021-03-31 Follow-up to 2021-03-13 Post
I'm a bit surprised not to see any comments about this question after several weeks, but for anyone interested, the Evernote software from the Microsoft Store (for Windows 10) is the same version as what's available directly from Evernote's website. However, updates occur through the Microsoft Store's 'Downloads and Updates' and not by other means. Perhaps there are other distinctions, but I am unaware of what they might be.
In my case, I uninstalled Evernote v10.9.10 (as noted in my initial post, above) via the Windows Control Panel. I then re-installed it via the Microsoft Store. In between these two steps, I installed Evernote Legacy 6.25.2.9198 (309198) Public (CE Build ce-62.6.10954), via download from Evernote's website.
Since then, Evernote v10.9.10 has been updated to v10.10.5. The 'About Evernote' dialog box now indicates: 10.10.5-win-winstore-public (83), Editor: v120.1.15587, Service: v1.31.4
As a result of these actions, I can run side-by-side, both versions (Legacy & v10) of the Evernote software on my laptop computer. I can also run Evernote within a web browser at the same time, although I don't see an advantage to do that.
I hope that this is informative and helpful.