D&D could do better at supporting high-level play, and building in options for apotheosizing the PCs and allowing them to punch the other gods in the face and take their stuff is a logical evolution of a lot of D&D campaigns.
This depends how it's done. It's not a contradiction to say:However, there are settings where most gods seem to be Tulpas, but most of the fantasy races were created by gods, causing chicken-and-the-egg question that a lot of settings do not address. If the gods created the D&D races, and the gods only exist because worship gives them power . . . how did the gods exist to create the races? Or how did the races exist in the world to create the gods?
That's kind of a mix of Category #2 and Category #4, isn't it? Where the gods kind of "transcend human understanding", but objectively exist and have probably been around for a very long time. That version of deities is definitely intriguing to me, it would be cool to see a world that was designed more like that. That is similar to what the worshippers of the Sovereign Host believe to be the nature of the gods of Eberron, but that isn't confirmed.For my own part, I guess I appreciate a sort of...inversion of the tulpa concept, one that still recognizes change and development?
That is, "tulpa" implies that a particular manifested thing gains power and significance until, eventually, some critical mass is reached and that mind-manifestation transcends the limits of those minds. It is, for lack of a better term, a thought(/network thereof) which gains apotheosis by accumulation (time, attention, fervor, adherents, etc.) It's loosely a "materialist immanent" theology:t gods arise purely from discrete material causes, existing only "inside" empirical experience.
I prefer deities with a more transcendental nature. That is, deities who have some form of inherent or "outside" existence/meaning, separate from pure materialism. I like it when Justice itself is, in some sense, innately divine. Such transcendental deities are more interesting to me because...well, to be blunt, people can think up anything. As a world-builder, it's much more of a statement, and induces much more texture, to have some particular thing or things be inherently sacred. That and, well, I have a pretty dim view of eliminative materialism and other uncompromisingly materialist philosophical stances.
This is part of why I love the 4e pantheon as much as I do. There, the gods exist and have transcendental natures, but that doesn't mean they are impossible to affect or overpower. Indeed, the primal spirits (an inherently immanent power!) drove out the gods in the wake of the War of Winter. Yet by slaying Tiamat, some of the books explicitly say it's possible to weaken the concepts that she represents: greed, envy, tyranny. Gold coins become no more than a medium of exchange, a tool to be used for benefit. Envy coils less around mortal hearts, transforming into appreciation or even aspiration, and jealousy softens into its own kind of appreciation or even generosity. Evil doesn't die, but it does recede in the wake of slaying a transcendent entity thereof.
I'm also not opposed to having the two meet somewhere in the middle. Perhaps the mantle of godhood is transcendental, but immanent beings can take it up. You see stuff like that in the Elder Scrolls games, where "Mantling" a deity is one of the forms of apotheosis.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.