I personally do not feel that N+1 is the necessarily correct number of bikes. But then I have limited storage space in my small home, and I don't see the point of having a bike gathering dust because you never ride it.
You could make changes to the Fuji bike. You could put on puncture-resistant tires and regular pedals. You can change it to make it more enjoyable for you to ride.
I could also see the argument for getting a hardtail that is less painful and more comfortable for you to ride. You could put less knobby tires on it to make it more suitable to paved/untechnical dirt riding.
When I was growing up, my father taught us to really think about big purchases before spending the money, to make sure the money is well-spent. If you're not happy with what you have, I think it makes sense to spend money either to change what you have or get something that works better for you, especially for an activity that contributes to good physical and mental health. This is why I bought a new road bike a few years ago. But then I donated the old one to a non-profit bike shop, so that someone else could enjoy the old one instead of having it take up space and gather dust.
Anyway that's my $.02.
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles