Do the thing that is hard over and over again! Too simple right? No, it is that simple. I get asked these types of questions all the time from clients about how to make getting up from the floor or getting off the couch easier. I don't have a list of magic exercises. Simply practice these functional movements until they are easy.
Get in your uncomfortable zone! Don't avoid the things that are hard, do them until they aren't difficult anymore. Get in the floor and make yourself get up. If one time wears you out, rest and do it again later that day. Do it every day. If getting off the couch is an effort, get up, sit back down, get up, sit back down... See a pattern? Stairs are difficult for many people, so find a flight of stairs and make yourself go up them each day or use a single step into your house if that is all you can find.
This can apply to anything functional. Do you have trouble putting away things on the top shelf of your closet? Find something that is a reasonable weight and put up then take it down over and over. Get in and out of your car several times in a row. Practice good body mechanics getting dishes out of the dishwasher.
There is no need to struggle with day to day activities. You simply practice until you succeed. No fancy equipment or "exercise" needed. Functional movements can improve your functional movement.