I ended up getting the 5900x instead, since it's actually cheaper than 5800x3D

But you won't have the same gaming performance uplift with 5900x, more for productivity. I also recently upgraded from 3600 to 5800x3d. Reason for upgrade was that R5 3600 was too limiting for 6800xt. But now you also have 5700x3d as a more affordable option.

It's not all that slower than 5800x3d on gaming but a lot faster in productivity (I use my PC on work more than gaming) so I guess the 5900x is an obvious one for me.

Yeah my 2700x was bottlenecking my 7800xt too much so I had to change it.

Funny thing is my old PSU can take my 7800xt upgrade but when I changed to 5900x, I had to change the PSU too

Talking about PSU, I am running adequately on corsair TXm 750W. What was your PSU previously?

It was a Hydro 650. No issues when I switched to 7800xt but when I changed to 5900x, as after powering it, the GPU wouldn't boot, GPU fans not spinning.

I'm currently using CM 850