My commute to the office is 37km, though nowadays I mainly work from home. I tend to go in once a week, so I do one journey by train (the office is right next to a train station which is handy) and take my bike on board and the other journey I cycle if it's not raining too much. In the pre-COVID times, I used to go to the office everyday and built up my stamina/fitness enough so that I could do both journeys by bike (weather permitting). It's not particularly difficult doing that kind of distance (I'm over 50) but it helps if you treat it as fitness training - 80 minutes cycling instead of 80 minutes in a gym.