smart view

I have a z fold 4. If I am using smart view to cast my TV to my phone, how can i screen record it? When I try to do it the video is just a black screen. Is there an app that will allow this to work??

Just so this doesn't come up in the answer - I don't have wi-fi or a smart TV, just my mobile data and a not-so-smart HDMI TV. I used to use my Galaxy J7 to connect to a Screen Beam Mini 2 via Smart View on my J7. I just got a Galaxy A21 and it turns out Samsung stopped making Smart View as of a...