You can do the opposite though, which I have done quite a bit. Use steady aim and then go prone, because going prone uses no movement. This gives enemies disadvantage to shoot back at you.If I have understood it correctly, the Rogue can't use Steady Aim (from Tasha's) if she has moved in the same round. Using the RAW, what about if she uses half her movement to stand up from a prone position, remaining in the same "square"? At a first glance, I would say no, she can't use Steady Aim: what do you think? Many thanks!
The next turn you won't be able to use steady aim thougj.