Surprisingly at least for me it has become 9mm. I've also gone from 4 9mm to a few. For a few decade I had a micro and mid size pistol and 2 Mac11's that went into exile in 94 for 20 years( I didn't understand Grandfathering at the time) until I turned them into carbines. Now that Carry is Convenient and legal I have added my EDC Max9 pocket carry with an optic, my shoulder, OWB Palmetto Dagger with optic, light/laser and my Sub2000. The Dagger and Sub2000 live in a grab bag with a pile of mags in case I decide that I need more than the Max9 for anything.
Most of my shooting anymore is for load development. Working through new bullets and powders to see if I need a new go to business round or stick with the ones I am currently using.
My maintenance shooting consists of 2rnds every few weeks from my EDC pocket pistol. If I can draw and hit 2 2litre bottles at 25yds in 3-5 seconds I consider everything to be working appropriately. It's similar every 3-4 months for the Dagger/Sub2000. This also lets me verify battery status etc. Sometimes if I'm at the range usually coaching others I'll go ahead and run a few mags at 25yds just because. Most people consider themselves proficient if they keep them all on the paper at 10yds. I show them that it's possible to keep them all in the 7 ring at 25yds rapid fire with a pocket pistol. Happy faces with the Sub2000 etc.
My other guns either live in secure discrete locations or my safe so other than battery checks or the occasional urge to make 5gal buckets explode like soda cans my other guns have a semi quiet life. I really need to pull out the muzzle loaders though. It's probably been over a decade but I'm sure they'll perform just like they always have.