if my mcu rewatch has convinced me of anything it’s that there’s no way in hell the government can find out about bob. bruce banner was hunted, samuel sterns was exploited for 16 years while in custody, and wanda was put in a straitjacket and a shock collar for far less than what the void did.
along with wanting him contained because of how dangerous he is, they’d practically be salivating over him science-wise. so much about his powers and how he even survived is unknown, and his durability alone is invaluable. there’s no way they wouldn’t be interested in replicating some of his powers or at the very least seeing how his body works. it would be really difficult to subdue him, but not impossible since we know that oxe was able to knock him unconscious and get him in that containment crate somehow. so if the government got their hands on him, the best possible outcome would be him in an indefinite coma, while the worst is probably years of inhumane treatment and excruciating medical torture…
and i don’t think anyone would be more aware of this than the thunderbolts, particularly bucky, yelena, and ava for obvious reasons. they would never let that happen to him. i think that’s why they seem to be keeping him so hidden from the public (not officially releasing his name, not including him as part of the team on promotional materials, etc)