The 8BitDo stuff is what I had in mind as well. Everything I have from them has Xinput mode, and works great for PC Game Pass and Xcloud games. I was hoping that anything that supports Xinput would be available on the actual consoles, but walled garden.
The 8BitDo stick has been pleasant to use, and is compatible with a ton of systems. Why is it banned at tournaments? Wireless? Or something else non-standard about it?