For a while now, you’ve been able to use XML-format .ytyp/.ymap files in FiveM and RedM, without doing a conversion between XML and PSO/RSC format: just make sure the .xml file is just named mh1_01.ymap without any extra extension, and it should be parsed and used fine.
Note that these are loaded using the game parser, so this may behave differently in some ways from CodeWalker/OpenIV’s parsers.