It would be nice to have custom unit insignias (in case the unit has sub-squads) without creating a proper mod.

Sorry for wasting your time.
After I tested -mod="C:\path\@mod1";"C:\path\@mod2"(works on ArmA 3 Launcher) I didn't look anymore to ArmA 3 wiki.

Hi Wizard,
"C:\Program Files (x86)\Steam\SteamApps\common\Arma 3\arma3.exe" -mod="C:\Users\<User>\Desktop\MOD ARMA\@agm;C:\Users\<User>\Desktop\MOD ARMA\@cba_a3" works, thank you for your time.
Probably I've done a big mistake, i suggest you to add an example like this, in the ArmA 3 wiki https://community.bistudio.com/wiki/Arma_3_Startup_Parameters (with multiple absolute mod path)