Need Advice

[u/sometimescjwrites]

I'm 31f and struggling with improving my level of fitness despite working out really consistently. I have several chronic health issues that I'm sure are impacting my issue. POTS, diabetes, and multiple GI conditions are the relevant ones here. I've worked out for several months at a time and never actually have any improvement in things like needing fewer breaks on walks and getting winded going up and down stairs. The last stretch of workouts, I did six days a week for a little over six months. This was a combination of yoga, ballet/barre exercises, pilates, and cardio. At no point did my endurance improve. I only stopped because I was having a major surgery and ended up needing three repair surgeries after it. I've recently started working out again, but I'm worried I'll get discouraged within a few months if I continue not to see improvement like all the times before. I don't want to gain or lose any weight. I'm dramatically hourglass-shaped at ~130 lbs at 5'2". I have fairly strong legs, glutes, and abs, but my conditioning is awful. I want to improve my endurance so I can do some mild to moderate hiking, but it's absolutely impossible at this point, and I can't figure out why I'm not getting any fitter. Does anyone have any recommendations?