I tried using the latest version of Fabric for version 1.17.1 with this mod and it straight out refused to load.
Solution was stated as "Remove Optifabric"

same as #394

a way to fix this, is by running version 11.7. anything above that won't work for now.

Its because Optifabric Is Not Updated So it does not work With New Fabric Version or New Optifine

Go To Minecraft Folder then Versions and Delete Fabric 0.12.5
install Fabric With 0.11.7
Use Optifine HD U G9