[databomb]

ClientCommand r_screenoverlay
and
host_timescale work on my server fine without sv_cheats 1.

If host_timescale gives you problems then turn off the cheats flag manually

SetConVarFlags(HandleToTimeScale, GetConVarFlags(HandleToTimeScale) & ~FCVAR_CHEAT)

but again, I don't believe it's flagged as a cheat.