Listened to some D1 officials a couple of weeks ago at a regional intramural tournament I was working.
“When in doubt, it’s not traveling.” You can’t come back down onto your pivot foot - that gives you two steps (pivot-non). But you can’t travel without control of the ball, either catching a pass or picking up the dribble, so it’s often going to be (especially when receiving a pass) a step before the pivot foot is established (catch-pivot-non).
So you can, and sometimes do, get a player who catches a pass, steps concurrent with the catch (left), takes a step and establishes the plant foot (right), takes the next step (left) then starts the dribble (right), picks it up after the next step (left), has the plant (right), takes the next step (left), and then goes up for a shot or passes. Seven footfalls to one dribble, and it can be completely legal. With high level athletes, this kind of thing can go a long way.
Shuffling the pivot isn’t allowed, but can be tough to catch, especially with a close defender when you’re watching body contact. That’s been something I’ve been personally working on improving in my own calls - good positioning helps
3 seconds. It exists, but referees are told to call it on an advantage-disadvantage basis (like most issues, just particularly prominent here). If you aren’t gaining an advantage from being in the lane too long it won’t get called immediately, though the ref should be talking and telling you to clear the lane. Then making the call if it doesn’t change.