I have a few health challenges and have been dealing with the same issues as you have also add in some vertigo (and a puppy jumping on me instead of 2 yr old haha). For me I tried ALOT of online and dvd beginner workouts or workouts that were for "core" or "lower back" etc etc and there always were so many exercises I simply had to skip altogether or so many I had to modify that I wondered why I was even bothering to do this particular workout at all. That became very frustrating and discouraging. The things that helped me the most as I gained more strength (and confidence) was doing Jessica's Walk the Weight Off 30 Day Plan, and her Feel Good Fusion dvd which is all standing also doing exercises from this website
https://darebee.com/workouts.html
On that site there are alot of challenges and I just would pick and choose a few of their paper workouts for whatever focus I was interested in at the time. Since there wasn't much modifying with these I felt more "accomplished". I have also put together my own "modification library" so now when I come across a certain exercise I have an equivalent I can now do pain free so I am slowly coming back to my dvd library without alot less frustration.