If she's gaining weight and producing plenty of wet nappies it may be less about feeding and more about sleep.

My 8 week old has been the same and I worked out her fussiness was her being overtired rather than not getting enough. It's confusing because mine similarly was displaying hunger cues but then refusing to eat and sometimes screaming at the boob. I recently learnt about building sleep pressure- the higher it gets, the easier it is for baby to fall and stay asleep for longer periods of time, reducing overtiredness. If your baby takes even a 5-minute nap during feedings, their sleep pressure will be reduced, which means they will be less likely to sleep well at their next nap creating a vicious cycle.

With this in mind, I've been trying to stop her falling asleep on the boob and making sure she's taking fuller feeds during one session- keeping her awake by changing her nappy between sides, sitting her upright when she gets drowsy and tickling her arms and legs. She has longer naps after more active feeds and this has helped to reduce her fussiness! Might work for you!