Hey, I had the same problem. Your game looks pretty choppy in your video -- even on the campaign map; I also had that . . .
I've put every setting at the lowest (the game looks terrible! It's disgusting) and it runs super smooth. So for me it's probably because either my CPU or GPU is bottlenecking and I need to upgrade my PC.

The default settings looked at my hardware and set everything to high, but my rig can't handle it. Obviously the game is still early access and will be further optimised, but there's always going to be a lot going on in Calradia.
I've got an old i5 4670k @ 3.40GHz (overclocked)
GTX 1060 3GB
8.0GB of RAM, but DDR3 (going to need to join the 2020s and get at least DDR4)
I'm going to start turning the settings back up and find the right balance between aesthetics and speed. Try doing the same and see if it helps.