so all comments turned off for some reason but i got a new one whoops

0:41 let's green screen that sh*t

the guy who fixed it probably didn't apply thermal paste, the CPU or GPU inside the switch is probably boiling which causes artificing and game crashes. The damage may be permanent if it is a thermal paste issue. the picture output is handled by the GPU. Not the CPU, If your switch was crashing with no artificing it would be an issue with the CPU. If its been happening every time you put load on the system its a thermal issue. Hope this helps you find a solution, Ask the individual who repaired your switch if he cleaned the internals after repairing whatever damage you sent it in for. And if he cleaned off the CPU and GPU thermal Paste/ Reapplied. This should help you get some answers If its not one of those two issues then it'll be much harder to find and fix. If its not a thermal issue and its something worse like a broken capacitor don't fix it use the money that you would use to fix it to buy a new switch.

Something must've gotten corrupted. Otherwise some main component on the board most've been damaged or maybe something shorted a chip.

That is so weird, is there any way you could report it to Nintendo or something?

never seen anything like it