Also, there totally isnt like 5 different ways for the players to rez a pc.

Depends on character level, setting, game tone. Not a universal solution to a universal problem.

And lets forget about habing NPCs do the rezing as a sidequest.

Not every game lends itself well to an unexpected sidequest. Also what is the dead PC's owner to do in the interim? This introduces a lot of questions and is also not a universal solution.

Did you read how defeat works in Fate? You can have death.

https://fate-srd.com/fate-core/conceding-conflict . If you don't want to go look it up, I'll summarize here:

In a conflict, before a roll is made, you can Concede. This is a Player action, not a character action. It means that you give up the conflict, but you get a say in what happens. You don't get whatever you were fighting over, but so long as the group agrees it's reasonable you can get something like "taken prisoner" or "left for dead." You also get a Fate point, which is nice. (D&D also has an extremely lackluster meta currency system, but that's a separate discussion). Note that it's not the DM just deciding what happens to you. That's for getting Taken Out.

If you instead let the roll happen, and you take more stress (damage) than you can hold, you instead get Taken Out. When that happens, you have no say. Barring normal social contract stuff, whoever was coming at you has free rein to just be like "And the spell explodes your head."

This is in the rules. To me that's much better than D&D's wishy-washy "maybe the DM will do this or that" standard. I don't want to hash this out at every single table I join from first principles.

D&D kind of sucks because it leaves a lot of important things up to the DM, so you get wildly different experiences depending on whatever half-baked whims this table has. And you have to have these conversations over and over again. And some people never will know there's other ways things could be, and leave the hobby or just be unhappy.

Some people might say "leaving more up to the DM is better" but that's wrong. Clearly going maximum calvinball "whatever the DM says in this moment" is not the platonic ideal of a game. At least not for me or anyone I know. Some rules are important. D&D is missing some important ones. And has too many rules in other places.