When I was 15 my grandfather took me out into the woods to teach me to drive stick in a 30,000 lb dump truck. I had never driven anything bigger than a golf cart before. My space to work with was a clearing maybe three times the size of the truck. I did not learn to drive stick that day.
Definitely not, I played GoW 2018 first. I loved it so much that I went back and played every other previous GoW before GoW Ragnarok came out. The others are very different (but still very fun) games, and it definitely makes you appreciate Kratos' story better, but they are by no means essential.