Yeah, I also didn’t pick that up. Carl Weathers’ character in The Mandalorian had a fatal wound but Baby Yoda was still able to heal him. It’s my opinion, but I think as long as a person is still breathing, a Jedi can heal them from even fatal wounds, but once they’re dead they can’t. That’s it. Ben bringing Rey back to life was an exception made possible by their bond.

The Prequel-era Jedi weren’t able to do heal others because they weren’t aware of the ability at the time, or their ability to use the Force were diminished at that time.