I've never had discussions about code formatting in PRs, this seems like a made up problem or something that predates my career.

It's not by accident that tabs vs spaces is one of the stereotypical great debates in programming.

These used to happen all the time. In one (otherwise great) programming course in university you would even get points subtracted if you did not follow the lecturer's preferred style.

(I think that in their case it was partially because uniformity made correcting faster.)

Silicon Valley (the TV show) memed about it with its tabs vs spaces bit. It used to be a thing for sure. It has been a good 10 or 15 years since I had such a discussion. Automated linting and formatting tools largely killed it in my experience.