I suggest using Zorrobytes system, it works much better than what I implemented. You could also trying setting your own preferences using the info here: https://community.bistudio.com/wiki/Arma_3_Dynamic_Simulation

I know Zorrobytes system it work good but you will get exactly the same issue if the friendly module is activated cause all opposing side close to each other will spawn and all the manned vehicle will be simulated, so the performance gain will be poor.
But i look at the AI in spectator mod wihtout friendly module its weird, so the simulation is disabled few sec after spawning, the perf are great but after few minutes a lot of unit are gradually simulated (every 2-3 sec). There something somewhere in your code that enable simulation.

I encounter an issue like this by using enableSimulation + dynamicsim (enable/disablesimulation will breack dynamicsim feature).

By the way i do a test by disabling dynamic sim in the Ao module and drop the BI simulation manager module, that take some time to transfer all the unit (to be cached) but when its done got good perf (80fps) in editor, saddly im not able to make it work on dedicated server.


EDIT : Got the same issue with the simulation manager module, after few minutes the unit are gradually simulated.
there something running periodically that enable simulation in your code that breack the dynamicsim or simmanager.
So its impossible for us to implent something that disable simulation because something in your code reenable it.

You should try to find and delete all the line "enableSimulation" in your script.


2nd EDIT : Every 3 sec that enablesimulation on a unit (1 by one) so check in your code where the AI are spawned there should be a line like this :

{
if...................then{
{
_something enableSimulation true;
sleep 3;
};


_something enableSimulation true; should be deleted