@Goku9001 I agree the scriptors doesn't think the same way you're portraying to, on their mind, Ssj Blue Goku vs Ultimate Gohan was just a motivation on Goku's part, Gohan's true performance is only shown when he got oneshotted by Kaioken Goku. In Z, 18 had a short exchange with Ssj Goten and Trunks, and yeah, this is Toei for you, I highly doubt that Toei's intention was to portray her on being Ssj Kids level, Perfect Cell was trading blows with Ssj2 Kid Gohan, I highly doubt that the intention is to portray Cell being on Gohan's level, especially when a powered up Cell got wrecked by said Gohan.
Yes, Toppo was holding back heavily on effort against Ssj Goku as he can compete with Ssj Blue Goku and wreck characters such as Ultimate Gohan, Ikari Broly tanked SsjG Vegeta, so the outcome goes without saying.
Ssj Blue Goku and Jiren were having a short exchange of blows similar to Gohan vs Ssj Blue Goku, yet, later on, he was dominating both Goku and Vegeta.
Now, could Goku have showed Kaioken against Gohan, had Gohan not seen it before? We'll never have a answer, but at least, for what the facts portrays it to be, Ssj Blue Goku could have oneshotted Ultimate Gohan the way Kaioken Goku could.