And by relying on this bug I can insert into an enemy turret as long as I use an inserter.

Turret force is looking more workable. The inventory problem is the only one that remains.

Changing the force works well for laser turrets, you can repair them and give them electricity. Only gun-turret is a problem.

I want using turrets to be more challenging.

The idea is that I still want to use them to defend my base (so they need to accept more ammo) but they just have a simple motion detector to find and eliminate targets and so using them safely is more challenging.

It will be possible to approach them ...

I would like to make turrets that attack the player that placed them as well as the enemy force.

I tried a few variations on the function game.player.force.set_cease_fire() but saw no effect. If it worked it might create more problems because turrets would also fire at turrets and other structures ...