You’re straddling some interesting AMD combos at those prices.

At $400, the Ryzen 7 - 7700x combo is faster at gaming than the 12900k and is fairly close in productivity, while using significantly less power (100-150w less). You can run it with a cheap PA120 air cooler and leave nothing on the table performance wise, unlike the 12900k which will need an AIO to avoid thermal throttling limiting maximum performance. Between the cooler and the larger PSU you’re looking at another $50-90 on basic system components in otherwise identical builds starting with the two similar priced combos.

For $100 more than the 12900k/7700x, or $50 more than the 14700k combo you can get the 7800x3D combo which, in addition to requiring *200 watts* less power under load, is faster in most gaming benchmarks. https://youtu.be/8KKE-7BzB_M?t=579Again, it’s fine to air-cool with a budget air cooler unlike either the 12900k or 14700k…

Factoring in the necessarily larger PSU and more robust cooling solution to avoid performance lost to throttling there really isn’t a price advantage to the “cheaper” 14700k vs 7800x3D combo in a total system build budget, if anything there’s a slight advantage to the AMD option if you are building net new factoring in a 200w larger PSU and a budget 360mm AIO like the $70 Thermalright Frozen Notte vs the $33 Peerless Assassin)

For a productivity focused build I’d hang out for another round of black Friday specials on the 13700k in a combo, I think that’s where you’re going to see the best bang for the buck unless they get crazy and do a cheap 12700k/13600k deal. I run a 13700k in my primary work/production and occasional gaming build vs a 7800x3D in my gaming-only setup where dual CCD / Xbox game bar core parking or e-core drama isn’t a thing.