In Short: Pretty Weak
From a review I posted elsewhere
Triple Frontier (2019)
Five ex-special forces operatives plot to murder a drug lord and take his money.
In short, this is pretty weak.
There are the usual heist tropes: 1) Getting the crew back together (tracking down old comrades, which involves seeing them perform jobs they hate; 2) The mastermind has developed feelings for his beautiful informant, a relationship which threatens to complicate matters; 3) The heist is perfectly planned, but something goes wrong. Something always goes wrong.
Oddly enough, Ben Affleck does not play the mastermind. That role, along with the leading man duties, falls to Oscar Isaac (which is OK because he's a stronger actor). The characters here are not terribly interesting, or humorous, or virtuous. One of the underdeveloped themes is that they've done nasty things in the past, and they have to find a way to live with the man in the mirror. Worse, they're doing nasty things in the present. Attempts to humanize them, or put a soft glow on their actions, ultimately fail. Just because you have a moral standard ("Brother: I won't shoot a kid who has a learning disability") doesn't make you're an upstanding human being.
Misc: There's an English guy doing a terrible American accent. Netflix spent a pretty penny licensing music from Metallica, Fleetwood Mac, Dylan and others.