The (sad) state of Tuta clients for Linux?

Hi, I know it's been brought up before, but it seems there's no "simple" way of running Tuta client on Linux (particularly Ubuntu / KDE Plasma):

- AppImage requires to be run in a terminal with ""--no-sandbox"" option, which is a known issue with AppImage in current Ubuntu apparently. It's possible to run Tuta this way, but tedious, and the client will not auto-update apparently.

- Flatpak, which tends to be my favorite way of managing applications, complains about missing secret storage (although that is set up fine), and will spin forever not doing anything

- for fun I even tried launching the Windows client through Wine (Bottle) and ran into "unexpected error" and quickly gave up

- Generally I'd actually be fine with Browser-only, but there I can't manage subscribing to URL Calendars (for whatever reason...! Please tell me the reason. Every other E2EE Mail provider I know allows this through browser client. Tuta doesn't.)

Happy for suggestions or info that this will be addressed.