I want to mention, those are exactly my symptoms.
Vibes in the two common ways of checking are low.
Autotune either gives me very low atc_accel, or it's wobbly.. (I wouldn't call mine twitchy.. Mine is always too slow.. Although w/ 3.3, it was sometimes twitchy.. Since then, it's been slow)
I mentioned a couple days ago I spent a few min manually tuning, and liked the results more..
I made a couple graphs comparing my roll/pitch vs desired roll/pitch. (I tried to get the scale and flight conditions similar)
The top one is my manual tune w/ Roll P&I = .09 Pitch = .12
The bottom is the auto w/ Rll P&I = .06 and Pit = .08
I haven't had a chance to auto-tune w/ 3.5 and a higher aggr. I will this weekend, and post results.