I'm a cyclist that rides anywhere between 200 and 500 Km a week (depending on the season) and does IF 20-4 from monday to friday. I usually eat after work at 4 PM.

You can absolutely do low intensity workouts in a fasted state and I regularly do so after work. In fact it helps burning fat reserves. Just don't overdo it.

On weekends, when I do my longer and/or more intensive rides I make sure to fuel properly though. I simply ignore fasting on those proper cycling days.