When I first wrote this, OptiFine was not yet updated to 1.17, while almost all of the mods I provide as alternatives were updated to 1.17.
Its support on Fabric/Quilt even isolated by itself is spotty. A large portion of Fabric/Quilt mods are incompatible with OptiFine. You don't have precise control over what features you do and don't get. Some of the major issues of OptiFine include: However, OptiFine since 1.16 does not meet its former glory. It offers some performance benefits, shaders, dynamic lights, zoom, and about a million other things in one neat package. OptiFine was one of the best mods, if not the best mod, in Minecraft versions 1.6 through 1.15. This exact same guide is also available on the QuiltMC forums: Why you shouldn't use OptiFine - Off-Topic / Minecraft
