Personally I really enjoyed both 2018 and Ragnarok, and got platinum trophies in both.
But I do agree that they do not feel like sequels to the original games. Kratos seems like an entirely different character, and the story kind of goes in the opposite direction.
It's very common for companies nowadays to make random games/movies, and force them into an existing franchise. It's cheaper than writing something new from scratch, and marketing works better.
It's not even about the games being good or bad. Just... disconnected from the rest of the series.
Take the Assassin's Creed series as an example. Black Flag was definitely a wonderful game, but it had almost nothing to do with the plot and universe of Assassin's Creed. Same for all other games since, except they're also mostly terrible games.
I feel like this is the main problem with new GoW games.