what should i use as a base for my distro?

hey yall, i'm thinking about making my own distro solely as a fun little side project.

but, as a way to at least have a bit of a base, i want to base it on another distro (sorry if i'm using the incorrect terms, i'm a bit bad with this kind of stuff). i wanted to use fedora but when i searched for help i found many people telling another user not to, so i wanted to ask the community for help directly.

as a person who is simply trying to make a distro for fun and as a side project, what should i base it on?