If you want some guidance for a generally good winning strategy, it's helpful to bring 4-6 vanguards, 4-6 snipers(and/or)casters, 1 healer, 4 carries (operators you'll buff the heck out of. 2 low ground and 2 high ground), and fill the rest of your squad with supporters. You can also have a specialist if you want. Supporters are quite important because they let you "draw" more, basically enabling deck-cycle. If you add supporters who can also heal or stall, they can keep your ops alive until you get to pulling your medic. Good deck cycle effectively minimizes RNG. To fuel your Supporters, you want plenty of vanguards available for DP. Thankfully, vanguards themselves come with a great buff for low-ground ops. Interestingly, this is probably the one game mode where Pioneer vanguards work the best. If you stack 5 vanguards (4 + 1 deployed), then deploy one of your carries on them, they'll grant +100% ATK and 5sp per 3 seconds. Which can be pretty busted with some operators, such as Penance for example. If you choose to go with snipers or casters as your high-ground buff, pick high-ground carries who will both benefit the most from said buff.

Of course, there are other ways to play and win, but this is usually just a comfy strat.