Automatic office file locking - does it work? next steps?

I have a mail reply from an official Nextcloud representative that the sync client does sync MS Office lock files (~$*) . I checked in my NC folder (in a shared subfolder successfully made availabe via groupfolders) and there is a lock file for a document I am working on, which wasn’t synced on macOS (can’t check other OSes).

I deleted the respective entry in the global ignore list in the sync client (so it seemingly was ignored out-of-the-box) which made the lock file available online and in the synced folder.

Unfortunately, despite the lock file being there now, MS Office didn’t open the document read-only from another test computer. This works without problems in our local network with our NAS, I have no idea why this is so difficult.

I don’t want to have my people explicitly lock a file or have them call up eachother informing them not to edit file XYZ.

Are there any new findings at the moment? We are currently having a law firm review our move into the M365 world. Oh wonder! This is not possible in a legally compliant way if you want to get any benefit from the functions in the end. In our area (consulting), we are not allowed to store almost anything in the cloud, so there is no real benefit. We are still on NC27 because of the lack of OCR support in the newer versions. Has anything changed in terms of filelocking?