After some tinkering around today, I realized I could stop using a cloud service like OneDrive for syncing if I could get Joplin on my Android phone to sync to an SMB share set up on my Windows PC (in my home network). But Joplin/Android apparently only allows syncing with local directories.
Is there way to get Joplin/Android to sync with an SMB share, or is that simply not supported yet?
I remember a discussion about this specific topic not that a long ago, but I cannot find it right now. In short, you need to install an app like https://f-droid.org/packages/com.wa2c.android.cifsdocumentsprovider, which should then allow you to add your network folder to Android, which consequently will allow you to use it in Joplin as well.
Thank you. That looks like a promising approach. I was able to get the Joplin Android app to see the SMB share this way. I'll test it all more completely after I get some sleep, to see if I can have all my devices sync without issues from this source.
I finally got time to look at this yesterday. With CIFS Document Provider running, and successfully connected to the SMB share, I was able to configure Joplin to recognize the SMB share and add it as the folder to sync with. But Joplin gives a really big error message when I tried to sync (I didn't write it down).