I've explained what works for me: action movie heroes. It's not going to work for everyone, nothing ever will. Not sure what else to say. If I brought every fighter I've ever run into a tavern they'd have plenty of stories to share because mechanics don't define the character for me. I don't think a character needs to be flashy in order to contribute to the team, spells and other supernatural abilities are never the most important things we look back upon.
So how about this. I've explained where I stand, and given a general outline of what my limits are. I've given a few ideas which get ignored. If you have anything else to say other than "you're wrong" let me know.
It's not actually that complicated - you're just saying humans (including demihumans etc.) have a limit. And outside that limit to achieve things they need help/ a boost:
Clerics get the "boost" from the divine
Warlocks get the boost from patrons (supernatural powerful beings)
Wizards get the boost from magic (whether it's the weave or the world or funny smelling mushrooms)
Bards get the boost from some deep connection to rhythm (or whatever)
So (for you) fighters don't get the boost unless they also get some external aid. Since this is usually in the form of magic items - maybe fighters can get some more formalized way to get the items they want? There can be more than one way to solve the issue. I'd argue that most DMs already do this in an informal manner.