Funny, I feel the exact opposite. Revealing that he'd had formal training for decades actually "fixes" what could have been a pretty problematic aspect of his character, IMO. It's one thing for someone with a super high "M-count" to have visions or super fast reflexes because they "see things before they happen" (TPM Anakin.) Quite another for a completely untrained Force user to lift enormous beasts, Force choke, heal, etc. From the very beginning I felt that he *had* to have some formal training or that F & F just went way too far off the rails with his abilities compared to even the Chosen One himself. Unless they want to say he's yet another illegitimate offspring of the most powerful Sith in the universe.
Now that we know that he was formally trained it does canonically throw out my notion that Force healing was something that was either a lost skill that Rey rediscovered in thousands year old texts or that if it wasn't lost that it was only trained to super high masters. If Grugo learned it while still in Force preschool then
it *does* beg the question as to why Obi-Wan didn't heal Qui-Gon, lol. But that issue is on F & F now and not TROS.
Until it's revealed otherwise I'm just going to assume that it is *not* openly taught and that it's a super rare and special skill that only a small number of Jedi can perform. Kind of like how Ezra surprised the much more seasoned Kanan by being able to use the Force to talk to animals.
I totally missed that while watching the show!
