Good luck with your experiment!
Admittedly, I rarely need OneDrive, so I’ve usually just accessed it with my browser when I’ve had to. Physical memory has gotten pretty cheap these days though, so as long as it’s encrypted with a sufficiently strong passphrase, the SSD might not be a bad idea!
If appropriate, there are also a few options like Nextcloud, but I’m under the impression that the E2EE feature on it is a bit experimental at the moment, so I wouldn’t use it for anything critical right now.
As for trying to make OneDrive itself work better, all I could find was this thread where it was mentioned that the CLI client should come with an automatic syncing feature (the --monitor flag). Have you tried that yet? Fortunately, it seems that Microsoft has been porting a few of their services like Teams to Linux lately (thank god, because I actually need to use that one regularly for work), so maybe one day an official app will be available for OneDrive as well.
Kiitos huomiosta! Asia on hyvä pitää mielessä vähintäänkin silloin, kun kutsuu kasvissyöjiä kylään.