12600k is 6/12 P-cores, 4 E-cores, 20MB L3 cache.
12700 is 8/16 P-cores, 4 E-cores, 25MB L3 cache.
For gaming, the 12700 generally beats the 12600k, simple matter of Lcache size since both cpus run the same 4.9GHz clocks.
DaVinci will use every available thread, so even just using the P-cores, it'll come out ahead. In any multithreaded workload, the 12700 wins. According to any benchmark available, in blender the 12600k comes in around 88% vs 1200k. That @ 8minutes savings on a 1 hour compile, every time it's used.
And that's at the 65w PL1, not the 125w PL2 which can push all cores at 4.8GHz instead of standard turbo settings.
That's worth the price difference. 12600k is $278, 12700 is $342, $64 difference single cost, and then consider the cost difference between a Z690 and B660/H670 boards.
B660, H670, Z690 are the same socket, same layout, basically the same motherboard ± some bells and whistles and extra components. The difference is in the chipset. I seriously doubt Intel would be stupid enough to not use a B660 and 13th gen cpu, like a 13100 or 13400 or even a 13700. You can stick a 11900 on anything that'll accept a 10 series cpu.
The only caveat to that is the board vendors themselves. They might decide that their budget boards VRM's are not suitable for the 125w cpus, so might preclude the 125w capability of the 12700 but be absolutely fine with the 65w PL1 values. I'd assume that'd follow for the 13th gen cpus too.