Security get everything the Insurgent forces get, then get decent weapons on top.
Security air support is incredible and purposeful, Insurgent air support is just variations of making the target explode.
The conflict this is loosely depicting (the general shitshow south of Turkey) has seen Russian Hinds engaged on the sides of groups Western forces have decided are the 'bad guys'. Advisers are supposed to have exotic weapons? What does the Insurgent Adviser get? The same kit everyone else gets. Why not give the Insurgents a Hind? Why not give their advisor the AK103 and AK105?
The PKM does not stand up to the M249 in most scenarios. Why not include the RPK74? Would give the Insurgent gunner the choice of playstyles. Why not include the MG3 or MG42? Both of these weapons have seen fairly substantial service in this conflict in the hands of the 'bad guys'.
Give the SKS a bayonet. Give it a "thing" it excels at which the Security forces don't get.
Separately but also:
The bullet sponge enemies (or the lack of hitreg, depending on what's going on) also dramatically favours low recoil high ROF weapons making the available Insurgent options feel really underwhelming by comparison. The M4/M16/MK18 can land a few rounds on a target with a good chance of a headshot or cutting through the kevlar and ceramic skin everybody is now made of, but the AK/G3/FAL at midrange are very hard to keep on target and a "few rounds" on target is a hell of a lot more challenging yet still required.