Everything works and there was some INI files and such I had to create/edit for my USB arcade controls. It just works. I don't want to re-map all those controls again to figure out switches and buttons. Plus WinXP is much easier to replace the LUNA so it boots into my menu.
This makes no sense.
Every week or so someone posts like this. They are usually either going back to a cab they built a decade or so ago, or they were gifted something. They want to redo the cab anew, but with WinXP because everything "worked" and they know XP like an old friend. It was great for its time.
Except that XP is outdated and nobody designs stuff to work with it anymore. Why would they? This includes MAME and the CRT_emulator/Groovymame software, assuming you actually want the best emulation possible.
Speaking of INI files, with Groovymame I barely need them anymore, at least for the display. GM just picks the best video modes and refresh rates anyway. You might be able to just port your USB controller INI files directly over to the new OS, and even if you can't the extra work involves to remap seems minimal. I don't know what a LUNA is, but it seems to concern booting directing into a front end menu, which is east to do in Win7 or 10.
I myself have been in a similar place, wanting to go back to WinXP, despite the driving force of logic. Initially I setup dual boot systems (XP/Win7), but eventually I just dropped the XP from my setups because there was no point holding on anymore. The only way is forward. Even Win7 is old, but at least it is still supported by the main software and hardware that we use for this hobby.
There are step-by-step guides on here for Windows 7 or 10. They walk you through setting up for use in a cab environment.