So I'm trying to follow the instructions from the old reddit community to build the miryoku firmware for [seeeduino_xiao_ble, chiper36, Colemak, default, Mac, flip, default, default, default, default].
That issue was specifically for revxlp (being one of the few boards that required a ZMK fork), not for xiao ble in general. Can you link your failed build run? I don't know chiper36, so unless it's compatible with an already supported shield (and you build for that shield) it won't be supported. See https://github.com/manna-harbour/miryoku/discussions/81. If you have a ZMK keyboard definition for it I can add it to Miryoku ZMK.