yeah this has been bugging me for a while and i keep putting off dealing with it. running a 4" on an F411 with some random 1404 motors i pulled from an old build, 3S. in angle mode it feels totally normal and i can fly it around no problem. the second i switch to acro it just starts oscillating like crazy on roll, feels like its fighting itself. pitch seems mostly okay which is weird.

ive already tried lowering the P gains on roll which helped a tiny bit but didnt fix it. D is probably where the issue is but every time i touch it things get worse or it starts filtering weird. i dont have blackbox on this FC which is making it way harder to diagnose obviously. temps on the motors after a short flight seem fine so i dont think its motor related but who knows.

running RPM filtering off because i thought it needed bidirectional dshot set up properly and i wasnt sure my ESC supports it. maybe thats part of the problem?

RPM filter without bidirectional dshot enabled is almost certainly your problem or at least a big part of it. if RPM filtering is on in betaflight but your ESCs arent actually sending RPM data back, the filter is basically doing nothing useful and you can end up with weird noise issues. either properly enable bidirectional dshot on your ESC firmware (BLHELI_32 or BLHELI_S with the right firmware version) or just turn RPM filtering off entirely and lean on your PT1 and biquad filters the old fashioned way.

also without blackbox you're really just guessing. even a cheap F7 board with blackbox onboard changes everything when it comes to tuning. flying without it is like trying to fix a car engine blindfolded.

could also be a prop balance issue specifically on roll axis if one of the props is slightly warped. ive had oscillations that looked exactly like a PID problem and it turned out to be one bent prop blade. worth just swapping to a fresh set before you go deeper into software stuff, takes 2 minutes and rules it out.