You should make a mod that allows you to create multi-block cannons/weapons.
Iron blocks for a barrel, perhaps length effects accuracy and speed.
Gunpowder blocks need to be inserted at the back of the barrel for each shot.
A striker block that triggers the gunpowder.
Lead blocks get propelled out the front of the barrel.

I'm not sure of anything like this that exists and it seems like if anyone could make it it's you.

I'm thinking like that game from the depths which allows you to build multiblock weapons but in minecraft

Sounds like a very cool idea but I don't think something like that has ever been made in Minecraft so it's gonna be a real challenge for anybody to try and do that