Bluesky didn't require phone numbers back when it was invite only, and then there was a period of time after they allowed everyone to create accounts where users need a phone number to verify. That requirement might have been replaced by a captcha according to:
Lots of services demand your phone number after the fact now, hoping to use the sunk cost fallacy to extort it out of you when you're in a hurry.
Walmart recently deleted my phone number from my account for vague reasons but most likely because another account had the same number. That other account is my wife and the number is our VoIP line. I have no desire to interact with walmart through my cell phone so I didn't give it to them. So I used a google voice number, which is not my number, to get back in. Then they just bought my actual cell number from my credit card company and autopopulated the field. Jokes on me!
https://github.com/bluesky-social/social-app/issues/2762
But I didn't try to create an account recently, maybe they went back to requiring phone numbers.