Build new pc with new gen or old gen

[Raizen]

Budget (including currency): $2500

Country: US

Games, programs or workloads that it will be used for: Gaming 4k

Other details (existing parts lists, whether any peripherals are needed, what you're upgrading from, when you're going to buy, what resolution and refresh rate you want to play at, etc): 

I want to build a new pc, I already have the mouse keyboard and Monitor, I got a 3090 a few weeks ago cause they were on sale it cost me $975 at the time it seems like a really good deal so I took it, however now I’m doubting about keeping the 3090, I can still return it and go for a 4000 series but with my budget(so from the original budget of $2500 there is only $1500 left ) I can’t get the 4090 maybe the 4080 but not sure and also I don’t know if the performance difference will justify the extra money.

 

The other issue is should I go with the old gen or the latest and greatest!?

 AM4 OPTION If I go team Red I was thinking 5800x3d am4 ddr 4 cheapest option

AM5 OPTION Not really sure which cpu but they are expensive specially the mobo and the ddr5

If I go team blue probably 12900 k motherboard that will use LGA 1700 so ram DDR4!? or DDR5!?