14900K is considerably cheaper in my country, I will have to go for it :/
Intel's 14900K is a
great CPU, don't worry. Compared to the 7800X3D, it's only a 5% difference at 1080p, according to HUB's tests. At 4K, it's basically the same.
The main considerations are the following -
You can most likely upgrade the CPU in the future if you get a 7800X3D since AMD will continue to use the same motherboard configuration in their next generation of CPUs. If considering the 14900K, Intel is probably going to release a new motherboard layout for their 1500 series of CPU, so if you want to upgrade, you'll have to get a new motherboard too.
If you care about heavily multithreaded productivity applications as well as gaming, then the 14900K is the better choice. The Intel chip has a large advantage for productivity applications, while experiencing only a small disadvantage at 1080p gaming, and not much difference at 4K gaming.
If you like to overclock your memory, you will have more headroom with the 14900K and could probably get better performance, especially in the 1% lows. However, that also requires that you know what you're doing and that you are willing to buy expensive RAM.
TLDR if the 14900K is cheaper for you, then getting it is a fine option.