1.21.4 mod building

yo

i want to play with this bizarre mod on the new version (1.21.4) and i need a lil help with build.
as far as i know, there is a file on github which allows me to make this mod work on new version by myself. if it is, im begging for help.

thank you.

all i got for now is couple files which i found here https://discord.com/channels/881614130614767666/882038774861819954/1302316023780999238