Problems with FP3 after installing Android 11

After updating to Android 11 some Days ago,there appeared some bugs.
I use two SIM-Cards from Vodafone and Medion, German Reseller ALDI.
The Indicators right up shows,both SIM not connected, similar Problem happens to other User after updating with several Handytypes.
Tested with Telephon,right,no connection. I found one hint, manually connecting in Register or Einstellungen in German, fixes the Problem. It works mostly. Now, both Indicators are with the small Cross for Not Connected, but both SIM works.
Second Prob, VLC, Videoplayer doesn’t work with hidden directories, with visible Directories, it works. Before updating, it works always with hidden Directories.
Third, some Apps frozen in Work.

Tjanx for help

Hi Ulf and welcome to the forum and the community.

If I have understood correctly, you are now able to make and receive calls with both SIMs but you are unable to establish a data connection (3G, 4G etc.)
Quite a few other users have encountered similar problems and these are discussed in the main A11 update topic here.

The problem is also discussed here.

For the VLC problem : is your app up-to-date? Ignoring hidden folders may be by design (see link below).
Also check out VLC info:

There’s discussion of a possibly related problem here.