Every single star, planet(colonizable or not), asteroid, etc has almost the exact same UI frame as a regular populated planet, right down to decisions and pop/army/corporate tabs at the bottom.
Just use the existing space station as the visual hub and add a few districts, features, and blockers to each stellar body dependent on its qualities and quantities. A building slot for the primary station with an auxiliary slot for defense structures, slave pens, or something. For stars just have the main station hub and 2 building slots for either science or energy production.
Have pops come from the nearest habitable planet or structure and I think we would actually see some of the organic growth that was one of the coolest features of early Stellaris before starbases even if it was a nice gameplay change. You could have incredibly lucrative asteroids or planets balanced with poor or hazardous work conditions. Balance tall and wide empires using our new favourite thing: pop growth. Give growth modifiers based on population concentration on the galaxy map, allowing you to stretch your border to get that special system or planet and build up from there hoping that boon would be more worthwhile than concentrating and expanding from a more stable base.
This would make habitats and several megastructures something of an upgrade to a basic station to represent it changing from the backwater mine it began as into the thriving hub of population, production, or research it might become. I think this accurately represents how human towns and cities evolve, around a place of importance in resources, trade, or just a nice area to live.
I have to admit I've seen a number of complaints that 2.2 did not solve the strain on late-game play speed and performance, and this suggestion would only compound those issues; however, I would gladly play on smaller galaxies if this was the depth you could find in a single system. I would even play with 1x habitable planet modifier as you wouldn't be so beholden to them for everything. There are plenty of mods that increase the scope of galaxy size, but I don't think it would hurt to look smaller.