Subj. Every time I’m trying to enable anything related to ray tracing (shadows, reflections, AO, etc) or path tracing - console spammed with error:
Assertion failed on expression: ‘data != nullptr’
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)
Tested on empty project, reported as bug (Case 1384449).
I get this as well.
Each successive alpha version is a decrease in performance with DXR ray tracing. It’s waste of time reporting the obvious bugs which disqualify this engine and encourage the transition to other engine. I think that now Unity buys more than he produces.
Alphas are alphas, previous one (2021.2a) also was a challenge to use, but it ended up with pretty nice 2021.2f2 release ). If alpha contains large amount of broken features and has a lot of bugs - all that usually means some big changes/improvements being implemented, substantial features reworked and so on…
Bugreport, bugreport harder! )
Yet this is why alphas and betas exist for us (so we can give feedback and report bugs early on). The other engine ™ also has experimental previews if you are into these things, otherwise maybe not use them if it’s not experience you like?
Nothing new, for me Unity Raytracing has been unstable/not working since its release, I do wish I had chosen Unreal a decade ago instead of Unity.
Yes, last time I also testing the same scene with UE5 and Unity (alpha) - UE5 (Early access) give mi about 30FPS and 2-3FPS in Unity. But this is from a13 - eariler versions was ok - but from a14 FPS dramatically going down and down and down 
The original issue reported by @Lex4art should be fixed since b1. Thanks a lot for flagging and reporting it!