My cardio secret, what works for me may not work for you but it's worth thinking about because cardio post op is extremely vital. I ride a stationary recumbent exercise bike.

Cardio itself is boring, when you are doing it and focusing on it you are watching the clock, focusing on your effort and speed which only reminds you how tired you are. The secret is to redirect your focus away from it and let your autopilot take over. To do this I have a rave music playlist I made with the beat and tempo of the music designed to control my speed and effort so I'm peddling to the beat of the music which removes my need to focus on my speed.

I enjoy watching the music videos because it takes my visual attention away from the cardio which prevents me from focusing on myself. I don't have to think about what I'm doing, how fast I'm doing it or how much pain I may feel and I can just enjoy myself. This makes it so every minute I am doing cardio is a joy. I don't look at the clock and think I've got x amount of time I have to do this but rather I have x amount of time I get to keep going. I have no upper time cap so every minute is just fun. I only have to stop when my body starts to complain and I'm not talking muscle fatigue, I mean complain like nausea or cramps.

Initially even if you feel like garbage you keep going because after 20-25 minutes you or at least I, hit a point where the endorphins kick in and the sluggishness, nausea, cramping, etc I felt before I started completely go away and the longer I go the better I start to feel until I am just fucking loving it! The secret is to distract yourself and teach you body how to do it on its own.