Just one thing before i go
My friend magnum - imo the best martial arts debater - used 23 tenkachi goku against monster Garou. Never seen that debate cuz i had some beef with the admin (inside fighting skills of old school era) and got kicked.
I thought about this match a bit. Dont take it too srsly, its just for shit and giggles - just wanna show that even pre Z Goku can hold his own against high tiers.
One thing about Gokus style: He doesnt have a style. You could say something about his crazy pace at the beginning and how he became more mature and learned how to switch from a lead agressor style to a counter puncher and vice versa. He sometimes fights like a guy with a muay thai background and modified boxing stance, american kickboxer, pin point karate and some good grappling skills ... but he doesnt really have a style. He sticks to basics and does wahtever suits the flow the best. Like Bruce Lee said "Be water my friend."
I could see teen Goku pulling a win maybe 1/10 times due following reasons:
He scales above some neat statements which gives him a very strong base, so in a straight up H2H he wont have many problems, Poppo and Kami training and KI control.
Copy: Copying martial art techniques/style is their job so i dont really see whats so amazing about it. Most of the time it isnt really stated how long it took to create said copied technique. Garou is one of the few were it is stated - it took masters some decades to create it. Not as impressive as Goku copying Hakai but in the area of Goku copying a technique which took 50 years to master.
Talent: What Garou achieved in 8 years is incredible. More talented than manga Goku but less than anime Goku who mastered the real angel technique in 45 mins.
Arsenal: Garou hands down. Even if Garou is lacking in some specific areas - compared to other fighter - that guy has so much fire power which allows to hold his own or even win against high tier guys.
The way i see this fight:
Dragonball has some good internal hax "resistance" or better survived and then theres Whis statement which could give them the benefit that KI control protects them. While they dont have any radiation feats, Garou doesnt have any feats going through a barrier made of spirtual power.
Goku wasnt that good when it comes to KI control so he cant survive for long but it should give him more than enough time to copy a strong attack from Garou and maybe beat him. Garou could do the same but the good thing and i was never so happy for Goku to be a brick, Goku doesnt have any strong "martial art hax" that Garou could copy.
Its short and nothing spectacular but maybe, maaaybe it could give teen Goku the win. 1 out of 10