How many flavors of “bandit encounter” are there?

[KorvinStarmast]

What if the bandits were a stereotyical murderhobo adventurer group

AD&D was full of that, as was the original game.

Set up the NPCs as needed to reflect some "adventurers" who have decided to make their current or future living by robbing and kidnapping. (Hostages bring in money). Party needs to find a way to stop them.
The "good guy" who led the bandits originally (a Robin Hood sort) died of the plague, or of an over ingestion of steel arrow heads in his gut.
The group has gone bad in absence of his leadership.

Standard fare.