Hmmm, it seems like you have the ultimate setup already, with two bikes for two types of riding.

A few years ago, I tried to pick out a "do it all" bike, but there were too many tradeoffs and compromises. I ended up getting two bikes.

1. a fast road bike for the spirited club rides. I have the bars set high enough that I can comfortably ride in the drops. For comfort, GP4000 tires on wide rims, effectively 26mm wide.

So at 170 pounds, I use 80-85 psi front, and 95-100 psi rear. And cushy Specialized bar tape. It's quite decent on rough chip-seal roads, and a blast to ride.

2. a gravel / adventure / century / light-touring bike. It has fenders and a rear rack.
I use anywhere from 29mm to 40mm wide tires, so it's great for all-day self-supported rides on the narrower tires, or gravel roads with the wide tires.
The bars are a little higher, and the gearing goes much lower.
This bike is comfy and really nice on any epic solo rides, but not as much fun on fast club rides.

~~~~~
A tiny apartment? a tower bike rack to stack the two. Perhaps ceiling hooks to hang them upside down (if it's allowed.)