It’s obviously doable coz others manage it, question is how long have you got to get some training? I’ve been doing ~25mile minimum round trip 4 days a week for about 9 years, was doing ~18miles for a few years before that. ~33 is the most I do semi regularly, I do the occasional monster commute days, but they wipe me out so not sustainable.
Upping the effort, an extra hill or a few more miles than usual can knock you on your arse so keep it steady. Offroad/cycle track you have the option to go as slow as you want to save your legs – but unless it’s well tarmaced it will add effort, even smooth hardpack is draggy. On road there are certain points where I feel a lot safer upping the speed to closer to the cars around me (taking the lane etc) so can interfere with an energy saving “slow n steady” riding style.
Killing yourself commuting can be demoralising if you’re not fit to do a “proper” ride at weekend…but if it’s just a short term thing probably embrace it all as free riding time, pedal your legs off, sleep soundly at night and rest at weekends.