Depends on the circle of people you're talking to... I'm not buying any phone without custom ROM support. And haven't done so in ages. I know several other people who've used LineageOS, GrapheneOS or Calyx at some point. I wouldn't say it's normal, but definitely not a unicorn encounter either. Just embrace it. You're a hacker now. Maybe this is a good thing. (Most certainly.)
I feel I should also say, times changed. Back in the day it was either impossible to run a Custom ROM because of some locked bootloader. Or it'd run perfectly smooth. Sometimes you'd be running a ROM of some 15 yo because that's the last person supporting that device. Today some things have changed. Security works differently. Lots of people use things like NFC payment that doesn't work that well without stock. More and more stuff has moved into the proprietary Google services. Cameras have become super complicated and AI enhanced. Running a Custom ROM feels very different from what it was 8 years ago. If you own one of the well-supported devices anyways. Because that was always an issue.