Bug [M1 Native] RecalculateGizmos taking long when there's a lot of scene objects and gizmos are enabled

Bug Report Case 1350835

So basically whenever there are a lot of objects in the scene and gizmos are enabled, I'm getting sometimes multi-second lag spikes with a frozen editor when selecting something in hierarchy. If gizmos are disabled the lag spike does not occur. The culprit seems to be RecalculateGizmos in profiler and it's directly correlated with the number of objects in the scene. This wasn't the case in Unity 2020. The bug report should contain a repro project but it's fairly easy to recreate, just clone an object a lot of times and select stuff in hierarchy.

 

I also faced this bug.
In my project, the editor freezes for 2 seconds every time I change the selection.
A annoying loading bar with RecalculateGizmos does appear.