Unity guys are having the exact same issue: Mac M1 stuck at 60 FPS? - #10 by Tautvydas-Zilys - Unity Engine - Unity Discussions
There’s also preferredFrameRateRange | Apple Developer Documentation and preferredFrameLatency | Apple Developer Documentation
It looks like Metal library is used in Unreal: https://github.com/EpicGames/UnrealEngine/blob/40eea367040d50aadd9f030ed5909fc890c159c2/Engine/Source/Runtime/Apple/MetalRHI/MetalRHI.Build.cs#L6
In the build configuration it links MetalCPP, MetalShaderConverter, Meta and QuartzCore libraries.
After reading through the list of files and the code a little, I found the Present function that Unreal uses to draw: https://github.com/EpicGames/UnrealEngine/blob/40eea367040d50aadd9f030ed5909fc890c159c2/Engine/Source/Runtime/Apple/MetalRHI/Private/MetalViewport.cpp#L440C69-L440C81
So I might be able to include a header and then set the variable on an object but atm I can’t find this CAMetalDisplayLink class and preferredFrameRateRange anywhere on github repo and in
source code locally.