On laptop with Ryzen 5 5500U (12 threads) it takes 50 minutes and on desktop with Ryzen 7 3700X (16 threads) it takes 20 minutes. I use all threads to compile the kernel.
It compiles way waster with Gentoo, because it has minimal config. I used the default config from Arch repos and modified it. It’s full of unneeded drivers, but I’m scared of disabling them. I already disabled wrong drivers a few times and had to use different kernel to boot.