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.
Shit take. None of the Soulsborne games are narrative driven. If you went into them expecting a clear cut story to be told to you, then that’s your fault. From soft is widely known for having deep lore that you have to discover and parse on your own.