I expanded on that request a bit in a new request. It's possible that a merge is the case (or not): https://protonmail.uservoice.com/forums/932839-proton-drive/suggestions/50833301-android-file-sync-extended

Setting up a new smartphone (when we buy a new one, lose it, or have it stolen) is a nightmare for anyone, and a large part of this tedious work involves files—any type, not just photos and videos. For those who also use their smartphones for work, which is extremely common, this becomes even more relevant.

I believe it's essential for Proton Drive to implement synchronization for any directory on the smartphone, and consequently, for any subdirectory as well.

To accommodate all use cases, the best solution is likely to allow users to select which specific directories they want to synchronize with the Drive at any level—and, very importantly, obviously to automatically synchronize all subdirectories of each chosen entry point. This way, we no longer have to manually evaluate the resource settings frequently.

Similarly, the ability to keep only certain files/directories available for offline and immediate access on the smartphone is also important and should be at the user's discretion for each file/directory.

Note: I opened this request as new because I believe this feature deserves special attention, and my perspective may be slightly different and/or more specific regarding this need than what has been specified in other requests.

We are switching away from Windows toward Android. Therefore, file sync is now extremely important.

Really expected this to be standard in any Drive service. Syncing across devices doesn't work if one of my two devices isn't supported.