I plan to abandon Onenote in favour of Joplin, providing I can solve my sync issue. Copies of all my files on my PCs are uploaded to the cloud on Proton Drive, I now need to synch Joplin between my home and work PCs (Windows 11) through Proton Drive. Joplin does not offer this in the ‘sync target’ setting and Proton Drive does not support WebDav. Can you give me simple instruction on how to achieve synchronisation through Proton Drive?
You don't have any great options. You pretty much need to stick with what Joplin supports and that's not proton.
Because Proton Drive doesn’t officially expose an API for access or automation, third-party developers can’t reliably build apps to automatically sync local folders with the service on Android. This isn’t just a missing feature — it’s a fundamental limitation of how Proton Drive is built (for privacy/security).
Proton does not support webdav on Android.
What can you do?
The Proton Drive client for Android does allow you to make a cloud drive folder available offline. If you have a specific folder on your Proton Drive that contains your Joplin data you can make that folder available offline and then tell Joplin on Android to use a local folder to store its data.
The issue is you will not have automatic synchronization and if you make changes on Android and Windows without synchronizing manually you will have conflicts.
After making a change on Windows and before running Joplin on your Android you must run the Joplin Cloud software for Android and let it synchronize the Joplin folder between the cloud and the Android phone. Once that is complete and I don't know how you know that it is you can then open joplin. If you make changes in Joplin on Android you must close Joplin on Android load the proton Cloud Drive software for Android and let it sync back up to the server before you touch your Windows machine.
There is a program on GitHub call Roundsync that can mount your Proton Drive on Android and synchronize files however it's not maintained an updated by the developer anymore and there's no guarantee that it's going to work well. The developer last updated it in 2024.
You can use a program called syncthing to synchronize files between Android and Windows. On Android you have to use the app called Syncthing Fork because the regular syncthing isn't maintained anymore.
These are your basic options.
Your best bet is to use Microsoft OneDrive which you already have an account for.
Your other option is to do what I do and pay for Joplin cloud.