I’ll just put a few words of warning about the “forever” bike idea from my own recent experience.
I had an aluminum gravel bike with mech GRX and carbon road bike with 105. Both were good bikes, but I had the idea of selling them both to get 1 higher end “forever bike”. I bought a Lynskey GR300 gravel bike with GRX Di2 last spring, and had 2 sets of wheels so I could tackle any terrain. It was prime COVID time so I barely lost any money selling the bikes and enjoyed my Lyskey for a bit last year.
To get a good road fit, I needed a longer and lower stem. I was on the road 80% of the time so figured that was fine…then got my butt handed to me on a few gnarly gravel descents where the geo put me too far forward and it was downright scary.
Fast forward to today…and I now have a Specialized Roubaix and Salsa Cutthroat. I can tackle any terrain by chosing the right bike. There are no more fit compromises…I need to be a bit more upright with wider bars to be comfortable off road. I’d be hesitant to buy a “forever” bike unless you know, for sure, it’ll fit well and handle whatever terrain you intend to throw at it.