Anyone have same problem in battles with more than 60 man on every side?

It's not just you, i get drops into the mid 30's to low 40's in these big battles (although in cities only for the most part), and this is on pretty recent hardware (i9 and RTX 2080). My guess is just the ai running for so many characters, especially in more complicated environments, but i have no actual idea. Weirdly though, the custom battles which have lots of enemies/allies in cities seem to run fine, so it's only in the actual campaign that i have this issue.

The good news is there is a patch out on steam that states performance improvements in battles in the patch notes - the bad news is it will probably take a while for that update to make its way here, as that has kind of been the past trend.