I wouldn't get an MSI and GPU because the one I have now has a bad heatsink and they have a rep for having bad heatsinks as well. Look for either a founder edition or a Aurus 2080
I don't know where to begin... First of all your playing games like fortnight or CS:GO so for ultra 120fps all you gonna need at least 480 Gb and since prices are down now, id go with that.
If you are focusing on video editing I think either a ryzen 5 2600, 2600X or even a ryzen 7 2700 would fit your needs but as far as GPU goes who then probably go with an RTX 2060 if you are not focusing on games as well 16gb ram just because getting an rtx 2060 will make your price drop.
You don't need 16gb ram right away get 8gb and get Ryzen 5 2600X plus cases just matter on size every other part is just preference. You would want a mid tower.