Since we already have a machine race (the Synth) maybe the scavenger race doesn't have to be part or all machine.
I was inspired by the Lost Fleet series by Jack Campbell that had an alien race called The Enigmas. They used a quantum virus to erase their ships from enemy sensors (cloaking devices don't exist in that universe). They were so obsessed with secrecy that when their ships were significantly damaged they self-destructed. During communication they used a simulation of humans instead of showing who they actually are.
The Hidden is a (bad) working title for my proposal.
Primary weapon: exactly like Sylandro probe except maybe not lightning. It can salvage stuff in the battlefield and can also do damage to the enemy
Secondary weapon: cloak
The strategy for this ship is to cloak and scavenge what you can from the battlefield (asteroids?) before your enemy finds you, until your power creep is strong enough for you to kill them. The Hidden ship should either be fast or have a long cloak, not sure which.
Basically The Hidden are a race that loves learning secrets and is paranoid about revealing themselves (hence the cloak). Also their ships are basically weak civilian ships (so they want the cloak to hide from conflict until they can run away or gather enough material to fight back with something interesting). The Hidden strip solar systems of their resources and technology. Maybe all of those resources are going to a rungworld and/or dyson swarm at their secret homeworld, just like those insectoids in the We are Bob series.
I'm just saying if I was a scavenger then cloaking would be second on my priority list. The first would be a good way to escape or kite enemy ships, but a kiting scavenger is more boring than a cloaking scavenger.
Maybe The Hidden are space Naked Mole Rats or Meerkats because they tunneled (hide) to escape predators in the ancestral environment (why they care about cloaking technology).