The (Bossfights) Afterlife, another plane of reality where spirits live.

So some sort of limbo
Maybe there is a flat place where the Traveler talks with Collector

No.
Only the Dead can enter this realm.

Traveler is half dead, he talks to the Collector through Limbo, maybe Limbo is a higher existence plane stuck between afterlife and living

No. That is what living ghosts are

And Traveler is half dead, his body on Earth, his spirit in Limbo

Unless he's fully dead
No

I get it he isnt in afterlife, he is stuck in Limbo, forever asleep, only death can free him

This is where the Mechanic lives I guess

Is he dead?

Yes
It’s in Phantom’s lore post

Oh oki