I think it will be difficult because MSFS controls works by receiving all hardware inputs simultaneously. That means, while it is possible to bind both pedals axis to both left/right brake axis. They won’t work the way you want it to due to the reason above. when you press the Left brake for example, it can apply the brake on both wheels as is configured. But since your right brake is not pressed, the sim is also receiving that command that the brake is not being applied. So the sim is receiving conflicting inputs at the same time. Is the brake being applied as instructed by the left pedal, or is the brake being released as instructed by the right pedals.
But it probably isn’t as serious as it may seem. For example, if you are still applying both brake pedals but not accurately (ie. Left brake is applying 45% pressure while the right brake is applying 47% pressure). You would only get a 2% discrepancy. Meaning the brake will jitter between 45% and 47% only, so your net braking pressure is basically 46%.
However, the less synchronised between your left and right brake pressure, the greater the discrepancy between the two thus increasing the amount of jitter that you’ll experience.
So again, it’s up to you. Technically you can bind all brake pedals axis to all left and right brake axis commands. But you need to still be aware that you have to press both pedals simultaneously with the same amount of pressure to minimise the jitters coming from both pedals input levels.
I’d still prefer you to bind the brake axis separately, it would help you learn and get used to the brake pressure that you need to apply in order to control your taxiing speed without turning.