I updated a 1.15.2 world to 1.16.1, and /c and /s do not work anymore. The shortcuts didn't work either in a brand new 1.16.1 world.

I have the following mods installed :

Edit : I tried to remove other mods and same result

Have you heard of this? https://github.com/gnembon/scarpet/blob/master/programs/survival/cam.sc
It's basically a Scarpet replacement for commandCameraMode (/c and /s).

/c and /s were removed since you can now do F3 + F4 and F3 + N

oh right thanks both !