pc has already had this with Xbox game bar and the perf impact isnt really noticable. if I recall correctly modern gpus have some dedicated chips for video rendering that are otherwise idle. I would assume there is some hit to vram that could hurt if you’re limited on it, but for most people it should be fine.
it does feel ambiguous though as even what you outlined misses a 4th case. if null means delete, how do I update it to set the field to null?