Unity 2021.2 Apple Silicon Performance Issues with DynamicGI.UpdateEnvironment()

Since upgrading my 2019 LTS project to 2021.2 to test Apple Silicon compatibility, I've run into issues with DynamicGI.UpdateEnvironment() using significant amounts of CPU every time it's called.

I know this is already a performance-intensive process, which is why I had it called on intervals. But on the Silicon build it's simply too much of a lag spike which makes the game feel jittery despite it feeling super smooth otherwise.

Specifically the issue seems to be due to the CalculateAmbientProbeFromSkybox method.

In my 2019 LTS (Intel, played through Rosetta) build I never got these lag spikes and would only see a linear FPS drop if I increased the call interval of UpdateEnvironment too much.

I really need to be able to use this. Any workarounds or is the solution to wait Unity out to fix this?