I have a 7800X3D + MSI X760E gaming paired with a GTX1080 until I upgrade to the RTX4070ti Super at the end of the month. GPUs are very expensive these days, but CPUs are relatively cheap, so I saw no reason to go with a slower (6 core) and less future-proof CPU. The 7800X3D is quite a bit faster than the 7600X (160 fps vs 101fps), and the price difference between these CPUs was not great enough to even consider getting a less powerful CPU.
The 7800X3D is amazing, it only draws 55W on average and even cheap endorfy fortis 5 was enough to cool it. I get 55-72°C during gaming, and up to 82-84°C in cinebench R23, with isnt a bad thing considering this CPU is designed to run at 89°C under full load at all times and pusth cooler to the limits before it starts lowering frequency.
If I had to choose between the RTX3060 12GB and the RTX4060 8GB, I would go for the former. Yes, the 3060 is a little bit slower, but IMO 15% better performance does not make a significant difference, so if the game runs too slow on the 3060, the 4060 will not offer much better experience anyway unless you turn on FG (frame generation) and I'm not even sure if you can enable FG on the 4060 8GB, as games are already VRAM-limited without it on the 8GB cards, and FG drastically increases VRAM requirements. However, the extra 4GB on the 3060 can make a huge difference between a playable game and an unplayable stutter fest experience. Some games, such as Forspoken, fail to load textures even at the lowest settings on 8GB GPUs.
My GTX1080 2GHz is obviously a massive bottleneck for a 7800X3D, but I'm still surprised at how well many modern games run on this 8-year-old GPU. I cannot run UE5 games at 1440p, but thanks to FSR it can run the vast majority of raster games at 1440p with a playable frame rate 45-60fps and that's perfectly fine for me on my VRR monitor and especially on gamepad. Right now I'm playing Hogwarts Legacy (1440p FSR quality and high settings) and I'm getting 65-80fps. If you use reshade sharpening filters, even FSR quality looks sharp (in Hogwarts Legacy FSR looks much sharper than native).
The biggest problem with the GTX1080 is poor driver support, as modern games are much more optimised for the newer architectures. I get low GPU usage and low fps in some games becasue nvidia no longer optimize drivers for my card. Two weeks ago I bought a 2080ti (I was planning to use it till 5000 series will launch) and these problematic games had no such problems. Unfortunately the 2080ti I bought was faulty (it's core was stuck at 1350MHz), so I had to return it. The 3060 12GB should have even better drivers than 2080ti therefore I would be happy with it's performance in modern games. In fact, I even considered getting the 3060 12GB when I realised that the 2080ti I bought was faulty, but I have decided to buy a new GPU at the end of the month. I was planning to get the 5070, but I think the 4070ti Super will still be a pretty attractive card when the 5000 series comes out, because I'm sure Nvidia will only give people 12GB VRAM in the 5070 series GPUs.