If you have a disease that causes organ damage, it's not that ridiculous. Look at the referenced studies. Multiple studies by different organizations performed 6-12 months out showing persistent fatigue, body aches, headaches, cognitive issues, loss of taste/smell, kidney function. Seems to be a real phenomenon.
I have not read the study you are referring to. Are you sure it is not specifically about hospitalized patients? Even then it sounds extreme.
But you are right that vaccines are clearly better when given a choice.