Jaeger
That someone better
Actually that's that not the problem. HP is fine.
Here's the thing, if you look at the damage of a 1st level spell and a 9th level spell...
Then look at the number of attacks a 1st level fighter and a 20th level fighter.
The 20th level fighter has too few attacks.
The 20th level fighter should have 6-10 attacks BASE with over 15 attacks with action Surge.
THAT'S the problem.
If the fighter progressed in combat like how the wizard progressed in magic effect, it would be the most annoying and unbearable class with its thirty minute turns attack fifteen times and moving hundreds of feet.
That's horrid LOL!
HP bloat is not fine, your extrapolation proves that the game will make itself completely unwieldly if you progress all the classes in the same way as Wizards!
A Prime example of different strokes for different folks!
I find D&D above 7th level to be a bit OP all the way around already, If I want to deal with stuff like that I'll play 1st edition Exalted!
E6 was clearly the best version of D&D never made...