If anyone missed it, Racket has finally (it has been planned and worked for few years now) moved by default to Chez Scheme (ie Racket CS) on v8.0 (Feb 2021) which has improved in most cases performance.
I think the aim was more for supportability.
I assume if you enjoy Scheme; you would like to write more of your language in Scheme and less of it in C.
Although that is somewhat contradicted by the plans to create a new syntax for Racket going forward.
Chez Scheme by itself seems to be extremely fast.