I tried to load in this mod in a fabric instance, and it displayed this message

 - Mod 'Dynamic FPS' (dynamic_fps) 3.4.3 recommends any version of quilt_loader, which is missing!
	 - You should install any version of quilt_loader for the optimal experience.

in that case, how do i even use this mod for its "optimal experience"?

but other than that, i can just run minecraft with this mod without any issues

You don't need to do anything, I just like the Quilt project so I put it as a "recommended" mod.
Maybe I'll remove this again in the future though since it seems to cause more confusion than anything ..