Keep in mind that *none* of this has ever been tested on WSL2.
Well, technically, the koxtoolchain `kobo` target has, since a few crazy persons have tried building & running KOReader in that in the past, and it apparently worked out, minus a few sanity health points, although I don't recall if that was with or without resorting to the koreader docker images

.
TL;DR: Cross-compiling is already a fairly nightmarish experience. I'd save myself some trouble and bite the bullet with a real Debian or Arch VM.