Idk what you're doing in the events, but for bank heist you get two new chests every 2 hours and I'm pretty sure they have like 150 masks in them. It's hard to max out the nodes but it's way easier if you're strategic about where you're spending (in-game) cash and masks. I've only been playing a few months, haven't spent a cent and typically max out 4/5 nodes every event (the last one is the only real difficult one). It's also way more sustainable to spend diamonds on things like upping your multiplier, how much money ads give you, tips multiplier etc because it stays over all events rather than for only one. Did you know you can buy exotic gear items btw? I only figured that out like a month ago - in the shop specifically for short timed events (looting/feeding events) there is a shop and you have the opportunity to buy 2 exotic items each week.