This has been a known issue for players within Germany specifically for some reason.
May be worth peeking into this thread.
https://www.coh2.org/topic/85654/input-lag-for-german-eu-players
Did you ever figure out the reason for this?
Since the quote didnt work somehow I'll post it again:
Ingame console. I dont know how to open it on a US or any other Keyboard but on the german one it's Ctrl + Shift + Ö for example. I recommend trying Ctrl + Shift and then some of the keys that are near the Enter button to the left side of it.
Oh, and you have to be in a coh2 match ofc. It doesn't work in the CoH2 lobby or main menu
Then you have to wait for the text line where it says
"MaxDelay[...ms] MinDelay[...ms] AvgDelay[...ms]" or something like that.
A normal value for AverageDelay during lag-free times is something like 70 or 100. But during the lags it's usually 500+ ms up to 2000ms
Nope I never found out about the exact reason but I am confident it has something to do with the infrastructure between certain german ISPs and this exact CoH2 server. Or else it wouldnt make sense that using NordVPN and connecting to e. g. a danish server, suddenly fixes the lag for the most part