using 3d skin layers with the popular performance mods make the game stuck at loading screen.

Please at least provide mc version, modloader, mod version, crashlog/latest log.

fabric 0.16.9 mc version is 1.21.3 mod version is 1.7.1

• Mod '3d-Skin-Layers' (skinlayers3d) 1.7.1 requires any version of fabric-api, which is missing!

You didn't install the fabric api (its disabled)

[✘] fabric-api-0.108.0+1.21.3.jar (disabled)

i did enable it, the game launches but it stuck at mojang logo reloading twice.

All I can tell you is that it works,

The log you sent just crashed because you turned off the fabric api. But that should also have opened a window telling you that you are missing mods.

Im aware of the dependency of the API maybe I have sent the wrong log. here is a vid:
Uploading Bug.zip…

Caused by: org.spongepowered.asm.mixin.injection.throwables.InvalidInjectionException: Critical injection failure: @Inject annotation on setModelProperties could not find any targets matching 'Lnet/minecraft/class_1007;method_4218(Lnet/minecraft/class_742;)V' in net/minecraft/class_1007. Using refmap skinlayers3d.refmap.mixins.json

That mixin is not part of the 1.21.3 3d skin layers file. Could it be that you downloaded the mod for the wrong version? 1.20.6 or so?

Seems like Prism somehow skips the mod version check, causing the crash when fabric api was missing instead of an info window, possible it also forces 1.20 mods to load on 1.21.3 for no reason.

since I switched my launcher from modrinth to prism I faced issues like this with multiple mods after importing my instance. maybe I will create another instance and test it. Q : am not expert in programming. am concerned that my logs contain some private info. Although I trust you, please relief my concerns :3

I think the most "private" thing they can contain is your mc name or pc username. They are designed to be shared without leaking anything important (tho they will contain chat logs when you play multiplayer, but crashes at startup shouldn't contain anything important).
Never used Prism tbh, I mainly use CurseForge launcher and sometimes Modrinth launcher, so no clue why it might behave weirdly. Best-case make sure you download the correct file from Curseforge/modrinth and put it into the mods folder, then it should work.

After trying it in a new instance I can confirm it is working! thx for your hard work. luv ur mod so much<3