If gaming is +70% of the PC usage go intel, and as writen above the Cpore i7 10700/F/K is a beast for gaming and most productivity software. But yeah you will want to spend on a very good cooling solution.
Now as stayed also above, the Core i5 10600K can also achieve the same level of gaming as the 10700, it will be cheaper and easier to cool, but some of the productivity work will suffer a bit (less cores/threads, less L3 cache). Then again if gaming is the main use, a fast 6 cores/12 threads CPU will still work fine for ACAD and any Graphic Designing software (my uncle is an architect and I have insisted him to upgrade his PC but he refused, he draw house, buildings and custom made tv and books forniture in ACAD, hes use the 3D modeling and all that with a Core i3 (2 cors / 4 threads), 2x8 GB of RAM and a cheap nvidia GPU-can't recall the model now-, at tleast I managed to make him use an SSD which has make load times a lot greater and he finally realized that was a worth upgrade lol, is not a flawless experience but its good enough for him).
As for the Ryzen 7 3700X is a well all-round CPU, which can be installed on many diferent price and features motherboards (Budget yet good B450, Budget B550 which will keep the PCI-E 4, and X570). The money you save here can be put on a better GPU or more and faster RAM. It all depends on your use scenario. And theres the next Ryzen 4xxx coming which should work without hiccups on all B550 and X570 mobos, and most likely on many B450.