They're dead/gonna die, right
Four Likely Scenarios
1.They are snagged on wreckage, and will freeze/suffocate to depth on the sea floor.
2. The ballast tanks worked amd they arrived bobbing on the surface, but with no transponder give their location and the door solely being able to open from the exterior, means they will suffocate on the surface.
3. A deep sea current might have blown them off course, and with no transponder and no propulsion, means they suffocate and freeze.
4. The sub likely violently imploded from the pressure at depth.
Yeah, with no means to locate them, it's looking grim.
Straight up looking for a needle in a football field of haystacks.