ah alright thanks

The recruited AI have an option on them to choose their loadout. You can pick exactly which class you want them to be. No need to delete and respawn them.

oh okay thanks, maybe the AI squad crewman and pilots are from destroyed vehicles, but when i tried recruit AI infantries to my squad, it sometimes recruits pilots and crewmen which i have to delete them to make it not weird lol

You can choose multiple factions, and choose subfactions. Using the 'select Units' option you can choose which specific units from that faction you want to use. That gives quite a bit of options. Also, when choosing factions use SHIFT and CTRL to multiselect.

It tries to only place crewman and pilots as crew in vehicles. If you see them on the battlefield, it should mean their vehicle was destroyed. The infantry tries to not use these roles. Of course it depends on the faction chosen as it may not have anything but crewman for instance.

For control of what vehicles you want used, look for the parameter setting about 'choosing the vehicles using the garage interface'. You can choose which specific vehicles you want to be used that way.

Hopefully those meet what you are asking for at least a little.

and also, blacklisting vehicles for the AI and the player to choose from the base

Suggestion: add a blacklist option for certain unit types like crewman and pilots for infantry and options to add more factions to the side. some mods seperate their armed forces for army, airforce, etc like RHS AFRF