Microsoft’s MakeArcade has been made “playable” on Batocera for the Pi 4 thanks to the extensive efforts of Vegz78!
Community made games can be found at https://arcade.makecode.com/ , and the way to download the appropriate ELF files ready for play can be found at https://vegz78.github.io/McAirpos/index2
This isn’t really an official process, it’s very much a “back-door hack” that gets the software in and sets it up to be able to run. Maybe one day it could be integrated into Batocera properly in the future?
You can check out the details and troubles faced as detailed on his forum post.