Camera no showing any picture

[MHver]

Using Lineage OS on an old Samsung A5 2017, I do get an USB Device showing in the Windows App. USB debugging is enabled of course.
But when launching the phone app, i just get a landscape-mode black screen on the phone, nothing else.
The windows app shows no picture.

EDIT: My mistake, I had to, of course, grant the phone app camera permissions. I do not recall the app asking me to enable camera, but manually enabling camera permissions in settings->apps->Vcamdroid worked

[cate02]

Windows app is working, and I gave camera perms to android app, but the android app won't scan the qr code. I'm stuck at the "scan the qr code", there is no "scan" button or anything
Oppo reno 5g