Yeah Navi is much less intrusive than people remember, she was really well done. And yeah Navi is concise and has a little personality whereas Fi is rambling and repetitive and just completely emotionless (yeah I know lacking emotion was intentional but that doesn’t make it enjoyable)
The way they were infuriating motivated the player and makes it satisfying when you beat them, so being annoying was absolutely the right choice. The last Pokemon games I played were on DS where your “rivals” were nice and supportive and non-annoying and they were boring and I would have fastforwarded them if I could have.