Hi,
sorry for this messy post, I dont have much time but here are my two cents.
We shouldnt use Batman as a measure stick cause with the amount of combat feats he has, you could create a multi galactic sized penthouse ... the entire anime world doesnt hold a candle to it. No chance.
Mr. Gohan
Grandpa Gohans statement goes hand in hand with Roshis statement of "knowing every martial arts technique".
The wording of the latter isnt as straightforward as Gohans but the way he asks the questions gives me the impression he must known ridiculous amount of martial arts moves.
The same book states that Goku is Earths greatest martial artist.
Statements like these were a big thing when it comes to "magic martial arts" mangas due multiple reasons (theres a reason why mangas are so cheap) and most of them wanted to keep it simple and pretty straightforward. We shouldnt forget the 80/90s used to be the thoughest era for mangakas where not having enough ink was still your best problem.
Sidenote: Grandpa Gohan knowing every martial art isnt BS. Fiction in general plays ping pong with laws of physics and violates logic itself. It just means that Granda Gohan does have every muscle memory possible with the perfect synergy, which isnt possible irl - the problem already starts with humans brain. Hey its fiction ...
Hakai
Another thing I want to add for manga Goku intelligence is Hakai. Usually technique like existence erasure, time travelling etc. are only copied by non martial artist. Techniques like the ones above are out of their reach from my expierence. Copying martial arts moves is easy cause thats their job, but seeing them copy exotic abilities like EE is rare as hell.
GoDs expierence
GoDs being jobbers/lazy by the end of their career doesnt really mean much when you are THAT old. Sleeping thousand or even ten thousand of years is like thorwing away 1-2 days for normal humans beings.
What we do know is they are fighters and their goal was to become the absolute strongest which means they spent a good chunk of their life in the ring.
UI going against their nature is a no brainer since Goku devlepoed its own version (manga) with emotions. Even Beerus managed to attain a form of UI. I mean "wasting" million of years training UI and still not reaching that level sounds hard but GoDs are almost immortal so who cares. Vegeta isnt "immortal" so he cant really waste that much time and thats why he didnt really stick to Ultra instinct. UI is the technique everyone wants - its the pinacle of fighting. Them doing a standing ovation just speaks volumes and just confirms they didnt lose the "fire in the belly" and deep down in their hearth they still want to achieve it.
I think its fair for both sites if we take 2/10 or maybe 1/10 of their lifetime as training time(?)
Beerus vs Goku battle
The skillful stuff in Goku/Beerus starts right at the beginning. We do know that KI is a skill that you have to master. The more KI you have, the harder it is to control. It seems you guys forgot the ridiculous growth during the battle which made the power even harder to control. For universes sake, Goku did a Albert Einstein movie - turned the endproduct into stronger waves to cause the least amount of damage to the entire universe. Imagin fighting a psycho like Beerus at MFTL+ speeds, doing all the nano skills management and trying to have some fun while having the lives of trillions in your back head.
Finding the right exact angle against Beerus is just the cherry on top.
If we add the 10-15 statements that gives Dragonball infinite size, it makes said feat even more impressive.
Goku predicting Hit
I wanna keep this short cause im not sure if I read it here. Its not impressive by human standards? With Hits body alone, there are 64 possiblities to destroy Goku during that hax. There are even more possibilites once you realize Hit can make said hax shorter or longer (nigh infinite possibilites). While it was never stated during the battle, Hits entire sthick is "improving" and him being 1000 year old/Best assassine of U6, such a decision mid battle isnt out of his realm.
No fking human in real life could predict that so cut the crap.
Bye.