This post is more about what power level do you like in your games for martials and what do you do to make the feel the way taht feels good according to that.
In my case my biggest problem is how unidimensional they are, so advanced 5e has done the thing for me. I think that if we play at level 20 i would do some hombrew to push them even further but i like how many options they have.
I of the opinion that low level martials are cool but lacking in options and level 9+ martial characters are underpowered AF. That has to do tht as I subjectively understand dnd everything is made by magic, so the limit of physical feats should be as magic, like lifting tons or demolishing buildings with blows.
So, do you like martials in 5e or would you rather them to fulfill a different fantasy?
Hot take, but I think the martial/caster power imbalance is imaginary, and has been even in 3.5.
It comes from people doing thought-experiment characters, like Pun Pun, rather than actual play. You can have a caster player say “I use this series of spells in such a way as to break the game” but in practice it happens far less often than “I murderhobo the NPCs to break the game” and is easily dealt with the same way. If your caster is just playing like a normal person and fireballs a dozen goblins or whatever, the barbarian great cleaves a dozen more, everyone has fun, all is good.
It’s not about breaking the game. To match a caster in damage you have to build a munchkin martial, and even so the caster will still be more versatile.
Thankfully the Rules Lawyer has an entire video about this that captures my view so I don’t have to write an entire post about it.
You didn’t address one of the leading problems of imbalance: groups who do like one fight per long rest.
That creates scenarios where the fighter can swing four times for 4d8+16 total, but the wizard can drop two fireballs for 16d6 to whole groups of baddies (effectively becoming like 64d6)
The adventuring day is garbage and so long as the game is balanced around it, there will be problems.