Definitely not from Paradox. Europa Universalis IV is 10 years old now, still getting regular DLC releases, and late game is still unacceptably laggy on 2023 computers. Like, 20 to 0.2 fps.
I have an absurd amount of hours in EU4 and I have absolutely no lag in EU4 on my desktop. And I can think of at least two times where Paradox has had a patch that really significantly increased performance.
How often do you play past 1750? That’s when the 5 second month ticks happen for me. Also 2-3 seconds between clicks in the macro builder when you get 3000 provinces or so, methinks some algorithm is quadratic. Restarting the game helps.
As someone that has played C:S 8 years ago and last year, I'll tell you, not really, at least, not from people like paradox.