Are you asking if CTB without Benzo is possible? Yes.
The most important thing is a clean SN (of course) and antiemetics are highly recommended.
Benzo increases the probability of success because, among other things, it helps to stay calm, but Benzo is not essential.
Of course, Benzo also helps to make death more pleasant.
Benzo can be useful, but you can succeed without it.
Everyone has to make their own decision.