Sorry for a complete tangent - I've been assuming gray OP's text in ask/show meant people were downvoting a post and it always weirded me out - now had to double check to confirm it's simply always grayed out (why though?)
IL2CPP is separate concern from how fast Unity performs in editor. Our best hope for better editor performance is they move the editor to modern dotnet, and it's actually quite possible this happens by 2023 cyclus [1]
For domain reload performance, 30s seems really a lot, I suggest you profile InitializeOnLoad calls in the editor - some 3rd party plugins have a nasty habit of clogging domain reload with stupid "check for updates" http calls and similar junk, I found it rather easy to clean up.