I did watch a video on how to sync Darktable to pictures on your NAS, but it required manually pulling down the images and then manually syncing them back up again, which kind of defeated the purpose of sync for me.

I’ve tried quite a few after leaving Nova a few years ago and have settled on Lawnchair. It seems to be the most stable and is under active development.

Yeah, just use the Beta, it’s extremely stable. Don’t get it from the Play Store though, as you’ve seen it hasn’t been updated in years. Just get it from their GitHub.