The only thing people keep saying is that a larger ship has more power and more firepower. That has not been proven
Okay let's try this again. The Enterprise is a big ship. The big ship has a pair of big engine (you can bloody see them). The big engines require a big warp core to power them (you can see it too). Being a big ship, it needs to be surround it with a big warp field, logically this requires big power.
If the big ship is not at warp, that big power can be used elsewhere.
We once saw the Enterprise enclose a big asteroid in it's warp field, grab it with a tractor beam, and move it with the ship's engines. All that required big power.
The Voyager is a medium sized ship, medium engines, medium warp core (again you saw them).
Voyage is a medium sedan, Enterprise is a big truck.
Fire power. Voyager carry's 36 torpedoes and has four launchers. Enterprise carry's 275 torpedoes and has two exposed launchers. Unlike Voyager, the Enterprise has been seen
to launch multiple torpedoes at the same time, up to ten simultaneously. So even though Voyager has twice the launch tubes, Enterprise can launch five times the torpedoes in a given time period.
After the TOS era, phasers are only used in sublight combat, not at warp.
Voyager can put the energy surplus not being employed by her medium sized warp engines into her medium phaser strips.
Enterprise can put the energy surplus not being employed by her big sized warp engines into her big phaser strips.
In plain language, the Enterprise can hit harder, it has more "muscle."