I think you can make an argument for any of (late) 2e, 3e (with without PF1e), or 4e.
2e has Kits and the Player's Option books and other stuff so that, by the time you get to the end...yeah it has a ton of stuff. I don't know it nearly well enough to go into the details, unfortunately, but everything I've heard is that late-2e was either a powergamer's paradise or an incredibly flexible tool to get precisely what your roleplay was looking for. You just had to look hard enough.
3e has ACFs, PRCs, dozens of "base" classes, many thousands of feats, etc. If you allow PF1e, it just gets even bigger. Of course, it also suffers some...pretty severe balance issues as a result, but for the savvy metagame-player, that's almost a perk. Having played both high-level and epic 3e+PF, I can say that it is satisfying to see a combo you've assembled actually shine, and the more care that went into it, the greater the satisfaction.
4e, while not quite as "moddable" as the previous two, had quite a suite of highly effective classes, some of which were new concepts not seen before in D&D (like the Avenger) or fully-throated in a way they had never been (like the Shaman and its spirit-companion). Many feats, but not as many as 3e; many combinable options, but not as many as 2e; and then the whole Theme+Background/PP/ED side to add your preferred spin on nearly everything.