I have Samsung UE40J5200AW and it has that screen mirroring feature. Whenever I try to use to cast from Windows 11 to this TV, the stream stops after few mins of playing.
I have no idea if Samsung doesnt allow to play full screen videos from casting devices or not. I have tried to connect both PC and TV via Ethernet and see if it will help, but its happening all the time.
Whats interesting it also happens when I cast via my lineage os phone and I checked it on different TV and had the same issue.
Whats your ways to cast videos from PC/laptop to TV?
You could try and bridge it with the steam link app.