Laptop carrying advice

Hi, I have been commuting on my bike for a while. It is around 12 miles each way, some road some gravel tracks, and I am looking for options to carry my stuff. I have a cyclocross bike (soon to be replaced with a gravel bike) but I currently carry my laptop (actually a MS Surface) in a messenger bag, or in a backpack. If I wanted to move this to carry it on my bike, what are the best options? Panniers? Seat pack? Something else? Thanks