Support symlinks and aliases in macOS
ProtonDrive for macOS currently does not recognize and not support symlinks and aliases.
This can make folders syncing useless as it is quite common to have folders sharing a different view (e.g. time based view using annual folders) containing links/aliases to original files residing in other folders (e.g. organized by bank or customer accounts)
see also idea "Create folder shortcuts" - same idea but just for folders. this idea asks for general support for symlinks and aliases

-
J.A commented
Any backup or object management software that recognises symlinks (hard or soft) in any operating system can end up with big problems.
Symlinks can create applications being trapped in loops because symlinks can create circular reference loops.