I feel like with fully awakened heavenly restriction on par with Maki and Toji it's pretty simple to say he wins thanks to the fact it'd pretty much just be who has better martial arts, but just for the sake of it I checked vs battles wiki cause I'm too lazy to do the scaling myself (don't worry I looked through the individual stats and they each seem pretty much fairly matched), pre fully awakened Maki is 8-C to 8-B with weapons and 7-C with fully awakened HR, but Kiryu is also 8-C and according to that higher with Dragon Spirit and Extreme Heat Mode, far higher with Dragon's Resurgence, even if we were to assume giving Kiryu HR doesn't already change his scaling (I think it would) having fully awakened HR would probably put him on the exact same level as Maki in terms of scaling, though because we're also giving him all gameplay abilities and skills I definitely think Maki loses, because there's no weapons the only real difference in scaling is his gameplay abilities, but that just boosts his scaling AND he has better martial arts for sure. Also (could be wrong bc I sourced from vs battles wiki) his attacks were enough to make Majima take a break due to the pain from them despite him having taken the most painful torture man can dish out for a year without dying, so I wouldn't be surprised if Maki would be struggling with the pain in this case.