The short answer is 12600K. The long answer will be 5700G. The very long answer will eventually be 12600K.
If you have a use case, describe it. It's important to know the aim of the purchase, otherwise people will just hone in on the advantages of each platform/SKU and we'll end up discussing pages after pages of hardware accelerated AV1 playback. It's also important to evaluate the full cost of the purchase, so we need the entire scope of the build, any existing parts may change the equation (cooler, case, dGPU, RAM etc).
For example:
- keep in mind most LGA 1700 builds will require a new compatible cooler or at least an additional adapter from the manufacturer. This will skew availability and cost, especially considering 5700G comes with a stock cooler in the box.
- DDR5 & high Z690 mobo prices pretty much kill the 12600K price advantage, if you want comparable value then DDR4 it is.
- the 12600K is a faster CPU than 5700G, closer to 5800X in performance. But then again, for general computing the 5700G is already overkill.
- the real value comes early next year with i5 12400 - 12600 and B chipsets, so the current discussion is about squeezing value out of expensive parts.