When to intervene when LO is fussing?

We have a bedtime routine and she goes into the bassinet for the night, usually just fine. She sleeps very well, other than waking up every 3 hours to eat.

Sometimes she has a fussy period an hour after we put her down. If she cries, I pick her up ASAP (I know a 6 week old can't CIO), but I don't know how long to let her fuss.

It's grunting, groaning, flailing/rolling (no swaddle because she can roll), some fiddling and self-soothing, but she often falls back asleep within 2 minutes if we don't intervene. Sometimes it takes longer, but it's hard to tell when we should intervene and help soothe her down, because she often winds down by herself and picking her up seems to get her more upset. We think she may be easily overstimulated.

Sometimes we let her go like 20 minutes if she is just fussing and rolling around without escalating and no crying, it's just hard to tell when to intervene??

FTM obviously 😅