I bet some obsessive nerd has converted DND to point buy (like wod, gurps, etc) instead of class and level based.
You get XP for stuff, and you can spend that as you like on all the stuff you'd get from leveling. Follow the recommended route and get a standard looking fighter. Or go crazy and buy nothing but hit dice. Or make a glass cannon by buying all the sneak attack dice and second attack (in case you miss) and nothing else.
Or, per this meme, buy superiority dice and maneuvers, and then also buy extended crit from champion.
It would be a mess. I think part of why dnd is popular is its comparably small decision space. There's just not a lot of room to fuck up your character