Question about ASUS Rog Maximus Z690 Extreme Glacial

So at that price I would go top-end, so an i9-12900K / KF (KF only if you don't want integrated graphics with the CPU), maybe an i7-12700K, would be a little cheaper. You don't have much else left, currently the motherboard only supports Intel's 12th generation, more will probably come in the future (Q3/Q4 2022 at the earliest).

As far as RAM is concerned, there aren't really any good/efficient sticks yet, since DDR5 is still in the "early stages". But in general I can highly recommend Corsair, you probably won't need anything less than 64 GB RAM (https://www.corsair.com/de...).