I emailed Mayflash a few wks back and told them it'd be awesome to have a PS4 to Switch adapter for us ArcadeStick users (so we can use our PS4 sticks on Switch fighting games).
They just responded with:
Thanks for your kind message.
We are working some adapters for Nintendo switch.
Please keep eyes on website for updates in the future."
Apparently they have a few different adapters in the works for Switch, so yeah, being able to use a PS4 Stick on Ultra SF2 would be great and save us the trouble of buying a new Stick.