With yung having recently released betas of all his mods for 1.21 to his patreons (the code is on the respective github repos and can be manually compiled) it's probably a good time to look into what needs to be done to update the Compat datapacks

Also I'm sorry for opening a porting issue I know how annoying they can be please don't feel pressured by this Issue and take the time you need

I rather wait till the mods are fully released before porting compat datapacks