Thank you! I uninstalled pretty much every app (then cleared all the caches) and it just recorded a 7min video. So, I think it's fixed.
I'm not sure what the app was...I'm just glad it's fixed. Thank you for your help.
If it can help, i had the same issue on my S10+. I recorded a video and after 20 to 50 seconds, it stopped itself.
I uninstalled 4 apps because of this thread, and magicaly, it works. I stoped my record at 3mn.
The apps were : Fun race 3D, Puzzle realm, Aquapark.io, 1010!color.
How can it be possible that an app like that (which didn't ask for permission on camera) can stop a recording ?
I will be aware now after installing an app !