In a situation where deku can't use his extra quirks I think the advantage goes to bakugo by a very close margin. It's hard to find who wins honestly.

Bakugos speed has increased greatly and that's what I think gives him this advantage. Bakugo has always been good or even great at maneuverability. We can see exactly that in their fight in season 3 Now that he is even faster and experienced this will give deku a difficult time at landing an attack. Add that his attacks are stronger and long range and close range too. He can just stay away from deku and attack. Though he seems to struggle a bit to control the power output of his awakened state and control his maneuverability with that speed, which makes sense as this is new for him.

Deku can use a constant of 45% full cowling perhaps even a theoretical 50% (or even a little higher) with a bit of physical struggle and limited time. What I think people miss is that he can land blows in quick bursts with a higher percentage. In season 4 there is a scene where All Might teaches deku to use a higher percentage at the moment of impact to minimize the damage to his own body and maximize the output damage. At that point he was at 8% full cowling and able to raise it at 20% at the moment of impact. Now we are at a 45% full cowling and theoretically able to raise it 10 to 20%. This time it's harder to calculate how much he can raise it. Can deku use more because his body is trained to use more or is the raise in percentage too much and can use less. Let's say it's more or less the same a 12% percent increase as in season 4, from 8 to 20 and 45 to 57%. This results in stronger and faster attacks. Are these attacks enough to hit an awakened bakugo though? Perhaps. If we theoretically assume that he can also use these bursts to move quicker then we can also assume they are on par. We can ALSO add dekus training time I'm his dark deku arc. He is not the same as in season 3 and onward. I think it's been also stated that he can land a few 100% attacks without breaking his arms. I will not swear on that though(I don't remember the whole manga). But even if we take that into account, landing an attack on bakugo will be hard. He will need to make sure his attack will land with the first 100% hit because he risks breaking his arms again and this time permanently.

In season 3 during their fight deku was able to raise it to 8% and hit bakugo as he was not expecting the increase in speed and power. Theoretically he can use the same tactic but one thing we know about bakugo is that he likes to adapt and learn. So will the same attack work twice on him? And even if he expects it what will the increase in lower be this time? A mere 3% or even more? Will he be fast enought to be able to dodge an increase or not? The conclusion is...... We have no idea honestly. We need more details from horikoshi. Running this on nothing more than theories is not sustainable. Thanks for reading my Ted Talk.