Thanks for all the info, I didn’t have notifications enabled and I just read all the replies 
I don’t really need more speed than my current Mikrotik routers but it was not clear to me if Mikrotiks CPUs are considered ASICS and if fast desktop CPUs would generally perform worse. I guess I that part is mostly sorted.
I am thinking to create a dedicated PC for routing and firewalling, but that is because I need some kind of WAF similar to what Cloudflare offers.
I crated this separate topic, so that I keep this^ one just about desktop CPU vs Mikrotik CPU performance.