You don’t need to hide the [3]/8 time signature. Just put it at the start of the piece and it will display as 3/8.
I wouldn’t call [3]/8 a “workround” - 17th-18th century composers usually beamed the 16ths in groups of 6, contemporary composers often don’t. Typing 3/8 or [3]/8 in the popover just gives you the choice of which style you want to use.