Several thoughts occurred to me as I read your opening post on this topic.
1) You compare yourself to others and fear that you will never be "as good" as they are. Perhaps this is a part of your getting older and taking stock of your life so far. But don't forget that when you see others' work (or piano playing, tennis, etc) you see their successes and not their failures. We all have our shoeboxes filled with stuff that just didn't do what we wanted.
2) You seem to be a very harsh judge of yourself. Being self critical is, of course, necessary for growth, but it sounds as if you condemn yourself for not having progressed further.
3) I agree with other responders here, who urge you to leave the computer and go out and shoot. Some of us seek intellectually to learn how to be competent at something and instead of our anxiety becoming diminished it only increases to the point where we feel inadequate and stymied. This is because the learning has become abstracted from the practice. Would you give your 11-year old a book on photography, or a camera?
4) You might want to try an experiment. Why not go out with your 11-year old, each with a disposable camera or two. Take a hike through the woods, or your town, or a city you have not been in for a while. Maybe a zoo, where the appeal of the animals will inspire you. Limiting yourself to 24 or 48 pictures, you will look around and suddenly see a shot that might be fun to record. Soon you will become more "choosy," as the number of shots remaining becomes smaller. Then, bring them in for processing. View them as 4x6 or whatever the print size will be, and see if one or two captures the feeling you wanted. Then, take your "real" camera and one lens, and go back to the same location, this time knowing what you want to capture.
5) Stop worrying about your kit's quality. I have lenses ranging from a $70 50mm 2.0 to a $5400 500mm 4.0. I frequently use my 28-135 with Image Stabilization. You can find thousands of words of disdain about that lens on many amateurs' forums, but many of the pros I know have that lens as well. It is not the kit that determines the impact of your images. When people look at one of my pictures and say "You must have a very good camera" I say "That was a wonderful meal. You must have quite a good set of pots!"
6) Forget about "learning" Photoshop, Lightroom, or other software. Again, abstract learning is meaningless. Instead, look at one of your images and decide the basic things that have to be done to it: is it too dark? too low in contrast? is there a jet contrail going past the church spire that you'd like to remove cleanly? Then, one at a time, learn the specific Photoshop skills you need for basic optimization. Don't worry about layers, channels, masks, etc. until the time when you absolutely must use them for a given picture. If you use only what is necessary, when you need it, you will learn a few techniques very well. To repeat an earlier point, trying to learn more than you actually need to for a given task can only be overwhelming and frustrating, and convey the feelings of inadequacy that will extinguish the flame of creativity.
I hope you don't feel I'm talking down to you in terms of the skills you do have.