My suggestion is to create a series Advanced Warfare techs that unlocks a cannon/mortar and/or missile turret, that works in a fashion similar to the Vanilla equivalent of the tank turret and rocket launcher. As these particular ammos are, well, explosive a minimum range could be implemented to help avoid friendly fire. Another AW tech could unlock a tesla turret, which would target a whole group instead of focusing on an individual, balancing this would be super simple as by giving it a charge timer would curve its fire rate, and by spreading its damage so that either the more enemies there are the less damage an individual takes or having it so that each time the electric beam jumps between individuals it halves

Enough about turrets, another idea is to get the reenforced walls similar to the bobs mod reenforced walls, and then a later tech giving 'shielded' walls or a shield projector that is very power hungry but adds a new layer of defence, esspecailly from flying enemies...

I am currently unaware of any mods that do any of these things but if anyone knows and/or creates a mod like i have described plz put it in the comments.