I was on supplementary oxygen for a couple of days in ICU and maybe one day in the cardiac ward. I had complications, though, as my heart rhythm and rate were really wonky for days, until I was implanted with a pacemaker. Then it all settled down.
At home, I spend my nights in a recliner for several weeks, but not due to breathing issues or inability to get into and out of bed. My digestive system was so stopped up from all the meds that I was only comfortable in a semi-upright position in the recliner at night. I was re-admitted to the hospital at 4 weeks post-op to get it all sorted. After that, my regular bed was just fine. I never had any issues getting into and out of a regular bed. Being a smaller guy and being in good physical shape helped me there.
I did meet one fellow who came home with an oxygen tank. He had heart surgery as well as a nasty heart attack. He was in my cardiac rehab cohort. His first day on the treadmill he had his oxygen bottle right alongside the machine. By the end of the 12-week class, he was doing just fine without it.