GeezerVison

I would break the ++ here out into a preceding statement. Even though the C# language spec guarantees the order of evaluation of arguments (not the case in other languages), it's still more explicit to embed the side-effect as its own statement above

There's 3 other places in this file where indentationLevel++ is passed into a method and similar to your other style suggestion here, I think we should rather have a PR after that to apply style changes consistently. Unfortunately the code has already too much vertical method length for my taste, therefore I personally don't see the value given the price of one more line but that is not a strong opinion and would still accept your proposed style changes if you feel it's worthwhile.

I'm happy with it as is

ditto

This would make it inconsistent with the existing style where there is one newline only between the many case statements, which makes it nice to read in logically separated blocks of reasonable size IMHO.

Well the current PSSA codebase style is such that I won't argue. I think blocks should always be separated by newlines (and would have included another newline below the if below if I'd noticed), but not willing to spend too much energy on it

I'm not a fan of the PSSA style either TBH (especially the long methods where high level context is needed). I suggest a follow-up style PR to make the whole file consistent with this style or define something like an editorconfig file so that we could apply the preferred format across all files automatically.