In the SpaceX video Starship Update at about 57 minutes Tim Dodd the Everyday Astronaut asks about how the Starship rotates from reentry orientation to landing (vertical) and Musk explains that in the future designs the rotation will be done at the last moment by hot gas thrusters (methalox).
Dodd then follows up by asking “are those then pressure fed?” and Musk's reply includes:
High pressure CH4 bottle, high pressure O2 bottle, and the great thing is that they don’t care what attitude you’re at. You can be at any attitude, any gee’s, any attitude and it will still fire.
The image shown in Wikipedia's Pressure-fed engine looks like if you turn it upside down you'll just blow pressurant straight into the engine. How do pressure-fed engines or thrusters work at "any gee’s any attitude" and not require ullage?
For more on that see answer(s) to What is and what isn't ullage in rocket science?