Yeah, 20 year old habits aren't overcome that easily. I haven't played D4 because I didn't hear even once that it's more worth playing than D2. However, I'm a bit out of challenges regarding D2. I've finished the grail, including runes, before we had terror zones... OK, shortly before. There are few issues, like finishing Infinity in single player, but I'm pretty close to a stereotypical German, so I don't feel much of a need because I have enough characters who are efficient at killing anything in terror zones worth visiting.
As a D&D geek, I've started playing Baldur's Gate 3, of course, and I think it's among the best computer "RPGs" ever, but l don't think that it's the kind of game that will last for as long as D2 did for me.