I think when it comes to the question how games have aged, a line should be drawn between 2d and 3d games, mostly because the more simple (and often grid-based) movement of 2d games makes it much less likely for them to be plagued by messed up or overcomplicated control schemes, as well as the fact that, due to technical limitations, early 3d graphics have aged horribly, something that 2d games rarely have to deal with.
With that out of the way, I’d say Mario 64 is probably the oldest 3d game that is not only playable, but can actually still be considered a really good game today. There are other 3d platformers from that era that have aged equally well imo: Banjo-Kazooie, Spyro, Crash 2 and 3. On the other hand, action games from that era are mostly terrible by today‘s standards. Gen 6 is a bit better, though I would say gen 7 is the first gen where the majority of games are still playable.