I pad will have screen capture apps with the switch you can use a capture card or a camera pointed at it although I don't know much about the switch side of things :)
iOS 11 has a neat built-in screen recording feature if you're updated.
For the Switch, you're going to need a capture card unless you're fine using an external camera.
It should be saving to your Camera Roll...
I suppose you could try other apps but not sure how much luck you're going to have if the native recorder's not working. Or just use an external camera.
I find when I make a screen capture video too long on my phone my phone won’t like it and end up not saving it. I don’t have this problem with shorter videos though. My guess would iPhone storage but I really don’t know what’s causing this.
GarageBand takes up huge amounts of space, as well as amazon music, and all your pictures and videos that people send you still take up space even if you didn’t save them to your camera rill