Dropbox keeps trying to download and sync files set to online only

An unrelated issue where a user is also suggesting some fundamental disconnect/incompatibility between Windows 10 File Explorer and Dropbox:

https://www.dropboxforum.com/t5/Dropbox-files-folders/Thumbnail-photos-not-showing-in-Dropbox/m-p/597118/highlight/true#M231845

The only, ONLY, conclusion I've been able to reach about my current issue is that it started when I began using this computer...my first Windows 10 computer. Everything else is iffy/sporadic and can't be replicated right, but I do still believe it's connected to File Explorer...I just don't understand why it would still act up when File Explorer isn't open/active. It's like every time I find a way to avoid the issue, the issue adapts and finds another way to act up. Previously I'd avoid opening File Explorer while using Dropbox (even though that's not always possible)...now it acts up even when File Explorer isn't open!

I've made sure the folders in question aren't being indexed. Cleared the items in question from the Recent Files list. (Even the folder they're in isn't showing up there.) Turned off previews. Tried staying out of the folders in question while backing up other files (though I shouldn't have to do this, how else do I mark things local or online only??). Even tried avoiding File Explorer entirely, though much of the time, this isn't possible, for obvious reasons, especially since the desktop app was discontinued. Don't have any other third-party programs accessing the files, that I'm aware of. The files trying to download most recently are music files which I haven't accessed in weeks/months; previously, it was e-books. Only thing I haven't tried is turning off my antivirus software, which is NOT scanning at the time I do these things. I shouldn't have to disable my computer's protection to get Dropbox to sync properly, especially since this wasn't an issue before Windows 10. (The other threads I've read hint that this solution doesn't work, anyway.) I'm actually getting anxiety issues regarding when I'll next need to start up the program to back up my files because will it try downloading everything again?

I think I may need to restart this thread since I've been talking to myself in it for quite a while now with no further solutions; browsing all the similar threads I can find, I see nothing new that I can try (though I do see that those threads were posted around late summer/early autumn 2020, just like mine). I can't exactly disable File Explorer. 😕 I'm paying to use the service, so it could at least work properly.