I think it's not about CPU either. I'm running on RYZEN 7 2700, usually speed 3. And it's still terrible experience late game. Especially now since I can compare to CK3, which is perfectly optimized. Sadly, HoI4 is a disaster in this matter.
That's still 4,1 Ghz. For a considerable speeding up of GSG performance you'd need higher clock speeds but those aren't really around.
I don't know CK3 but probably it's a lot less complex computation-wise.