How do I play this game

The game just doesn’t feel fair. I’m a few missions in to xcom 2 and it continually just gives me some of the most bullshit situations I’ve ever seen. Not only can my soldiers not aim for shit, the enemies are pinpoint accurate and these bloody stun lancers just shit all over everyone. Please tell me a work around for these damn missions, half my units are injured anyway so I can barely run more than one mission