so whats the tactic with contracts so far?

If you hover your mouse over a chest it shows you how much alert it adds, the small chests add very little. Open all the small chests that are out of the way, if there's a big chest save it until your alert is almost full, make sure you are clear to the objective, grab the big chest to trigger the alarm and make your way to the objective grabbing any small chests you saved along the way. I think it's probably possible to grab every chest in every contract. Just pay attention to the mini-map and don't head off into rooms without chests killing unnecessary stuff, at least until after lockdown. Then you can kill everything.

the tactic is do all the hard work let ggg servers disconnect during your escape then ragequit alt f4 delete this game

So far it's just try to level your helpers as you go. I just hit lvl 51 and several of the heists are no longer available because my henchmen aren't the required level. Just having to farm low lvl acts to get heists to lvl the henchmen is bad.

The majority of the heists are grab and loot as much as you can, while attempting to get the big loot so your henchman can get better xp. The rest of the heists so far are quests for current/new henchmen so they can also be leveled. I'm averaging about 1 heist map per 3 areas, so it's pretty far behind.

I was trying to open all doors first, then open all the chests and trigger the alarm, then hurry to the relic room, but when the alarm triggers certain doors re-close... which is crazy, they should only close doors once the 20 seconds are up i thought. So not doing that anymore.

Honestly dont know what the strat is, i did a grand heist and all i could gab was 1 big chest before the alarm meter was at 80% (from walking through/killing mobs and grabbing the big chest) and there were still 3 other big chests and 20+ small chest left to go.. so it kinda feels bad right now.. maybe im missing something though. want to hear from others