You’re in a similar position to me then. I commuted every day for about 4 years before doing any structured training. I actually overreached (I think) whilst JUST doing commutes as I loved racing my work friends to work most days and I got quite addicted to high (what I learnt later to be known as v02 max) efforts. It was horrible. I actually didn’t realise that the riding was causing it and I was worried that I was seriously ill. I actually self diagnosed myself with chronic fatigue. It took a long time to recover from.
So, first of all I understand where you’re coming from, I just want to encourage a cautious, sustainable approach. After all, you COULD train more now but if that digs you into a hole that takes you months to recover from, then your abilities on a bike in 3 months from now will likely be lower than if you’d trained a little bit too easy all that time. Tortoise and the hare kinda scenario!
Also, my concern isnt just one of volume, but of intensity too. High volume has, if i remember correctly, a fair bit more intensity (hard workouts) per week than low volume (which is what I do). There’s nothing stopping you doing the low volume plans (3 TR rides per week) and adding additional volume that is zone 2. That way, you’re not reducing your training time or hours on the bike, but just distributing those hours across levels of intensity that might be easier to adapt to from the beginning and keep you away from fatigue that could cause trouble further down the line.