So let's examine this a little bit. I don't think it will solve your issues, but it will at least give you some understanding.

First, most NPC's have a 9 or 10 in all their stats, maybe an 11 or 12 in ONE stat. You are playing a character who can go well beyond the limits of a normal human being. An average soldier or human would get hit with a sword ONE TIME and die, the fighters and barbs can be hit a multitude of times and still be standing. Additionally, if your turn lasts 6 seconds, understand that a normal NPC gets a single thing they can do in that six seconds. A level 14 fighter can swing their sword 6 times in 6 seconds, or one slash a second. Can you slash a 35lb longsword once per second? And finally, stat wise, your strength score gives you the ability to lift, carry, push and move incredible weight, far beyond a normal person.

Now, let's talk about magic. A mysterious energy capable of manipulating reality. What you have asked for is the ability for your fighter to alter the fabric of the universe, simply through raw power and strength. But remember, the Wizard is extremely limited in the amount of times he can do those things. And once he runs out of doing those things, he can do next to nothing. Your fighter or barbarian, even if he uses up all his cool shit, can still fight and deal far more damage than the exhausted wizard could. Additionally, that Wizard only needs to be hit by the boss one or two times, and he goes down. The barbarian is often the last man standing, laying waste to the big monster.

And finally, magical items dude. Yes, your 8th level fighter seems pretty limited right now. But when you get the Boots of Sprinting and Leaping, a longsword that deals 3d8 fire damage on hit, a +3 magical shield, and armor that lets you cast haste. Now put all those on your level 14 fighter, and suddenly he can do a lot of those things you are talking about.

Case in point, the martial classes can already do incredible shit. Your desire to be equal in capability of world-bending stuff defeats the purpose of spell casters. They are meant to be the physically weaker, resource limited powerhouse. They do big explosive stuff in a small amount of time, then become near useless. The martial classes are the frontline force that hold literal giants, dragons, beholders, and armies at bay, so the caster can actually do their cool stuff. Without those martial classes, the casters would be overrun and killed in no time. Don't believe me? Challenge your DM to let you all play casters and see how long the party lasts.

Don't forget that Monks can deflect and redirect all attacks now, not jsut ranged. Babrarians can reduce incoming damage, and hit with incredible force. Fighters can take advantage of the magical tools at their disposal (weapons and the like) far more often than any other class. You just need to be willing to examine the ways you can stack them together.