You just move the panels around. Only extra panels get bought for vertical mounting a gpu.
I put a 240 on the back and rear. Just small stuff as it doesnt support 360's like the non air.
It was an upgrade over my 8700k. Still struggles and holds my card back. Not worth dealing with the heat, I'd look into a lower end 12/13gen. Thinking of doing the same, somewhat newer I7 with a cheap ddr4 board.
9900k struggles enough with a 3090. I get by in a few games but also not getting peak frames. I'd go cpu over gpu but since you just got it, could alway use a frame cap on the new card if need be.
Cpu is gonna struggle in everything before the card is the limitation.
Good for solo play, wouldnt do online unless is something matching the gen of the cpu, like bf4. Stuff around there.
Mine struggles with a 3090. Dont care to push the overclock to run at such high temps for little return.
Other games like 2042 exaggerates that as it pegs every core. I'll be upgrading to a 13700k, no need for me to struggle with this cpu with the next wave of games coming out.