I just got an update for my A51. It included a screen recorder feature. I tried using it but it didnt worked and after some time, the icon then disappeared from the notification panel. If anyone knows how to solve this please do tell.
Try doing this. It helped me. Go to settings > Apps. Find Samsung Capture. There should be 3 dots at the top right corner, it would gave to option to Uninstall updates. Do that. After uninstalling the updates, go to Samsung store and update the Samsung capture again. It should solve the problem. The screen recorder should be in the notification panel, if not then drag it down from the button order.