Advice: High Speed RAM with a 9700X or Lower speed with a 9800X3D

I plan on upgrading to AM5 and found two lots of RAM (both on the used market), both 32gb DDR5,

5600Mhz CL36 Corsair Vengeance for $500Au (360 USD)

6000Mhz CL28 Klevv FIT V $560Au (400USD)

I was leaning towards the 9800X3D, as I know RAM speeds become far less important when paired with the L3 cache on X3D CPUs. However, I can pick up a 9700X for AU400

However, I also came across the Gigabyte B850M AORUS Elite, which claims it can achieve similar gaming performance from a non-X3D chip to the X3D versions. (Not sure how reliable this claim is) I'm not set on this board, but it seems to be one of my best options for the price (260) among white mATX boards.

My question is: what would you go for? re: overall price-to-performance for general AAA mainstream gaming on a 1440p/4k display with the possibility of VR gaming in the future.

1. 9700X + 6000Mhz CL28 = AU960 (690US) (9700X possibly matched to X3D performance via the gigabyte mb)
2. 9800X3D + 5600Mhz CL36 = AU1070 (770 US)
3. 9800X3D + 6000Mhz CL28 = AU1130 (810US)

Any perspective is appreciated; thanks in advance.

(GPU will be a 9070Xt)

Coming from: 5600X, 3070, 32gb 3600Mhz