Sorry, I assumed wrongly based on your discussion you had very high speed projectiles (bullets). Your game may still need those, but it is probably true that most games don’t need such high velocity objects to track collisions. A shoot-em-up, for example (galaga, etc), running at 1/180s simulation steps should easily behave correctly with reasonably sized enemies where bullets only collide with enemies.
As long as all walls (including any objects that can collide) are thick enough where your bullets velocity prevents it from moving from one side of the wall (outside) to the other side (outside) then you’re good to go!
Just need to make sure that bullet can’t travel through smallest object and you can just use regular physics w/o CCD:
|max_bullet_velocity| * 1 / step_per_sec < min_wall_length
|max_bullet_velocity| = bullets top speed (units per second)
step_per_sec = 180 in your case
min_wall_length = the smallest distance (in units) that any wall or object has from one side to the other