It depends a lot on personal preference and what you want to use it for. (Families with a lot of kids need something like a minivan, some people need a truck with huge towing capacity, some people want good gas mileage, etc.)

My personal opinions:

* Ubuntu - when you want something well-supported and everything usually just works out of the box

* Pop!_OS - same as above but gaming is more important to you

* Debian - when you want stability rather than the latest features

* Arch - when you want control over every aspect of your system

* CentOS - when you want a rock-solid server platform (though this has changed very recently)

And there are dozens of other flavors of Linux with different strengths and weaknesses and different levels of support.

So it depends on your goals!