I’m certainly not ZLO but I can answer how to deal with air snipes.
First and foremost, scout. Know when the enemy has t2 air, and also try to know what the first few units they’re making from there. If it’s gunships/mercies/corsairs then plan accordingly.
Secondly, get flak. In basically any game your ACU is towards the front a flak should be one of the first t2 units you make.
Shields are important. UEF and Aeon should get mobile shields on their com. Sera coms can’t get mobile shields until t3, but you can get nano and t2 to get more health and more regen to survive.
If you’re Cybran you need to be especially careful, you have no shields and the weakest ACU. You probably need to stop using the ACU as much as the game starts getting into the t3 stage unless you have really good intel.
As the game progresses your com should be in your main base with multiple shields. Intel and not losing air control is the key. If air control is gone then sams. Have very good Omni coverage vs Cybran for their stealth strats, and again be constantly scouting.
in my opinion upset victories are harder in higher ranks because stronger players are better at not losing from a winning position. I don’t often see top 10 players throw a game they’re winning hard. Granted, upsets still happen but probably less often than lower ranked games. It has been a long time since I’ve played low rated games though so idk for sure. Full share and non full share both allow for different kinds of upsets. They’re probably more common in full share games honestly.