Kudos to you
@Dagamorn for bringing up a difficult topic and opening up to advice and encouragement! My main point I want to make is, do not be discouraged! I believe you have it in you if you came here and if you asked for support. I may be able to relate to some of these feelings you've had, so I'll start by describing some similar experiences, which is my preferred way to establish shared understanding. After I give a few examples, I want to explain how this program is helping me with them, and how you may be helped too!
First, I definitely get the difficulty of soliciting feedback. People often don't give it readily, and asking for post-mortem comments feels to me like either fishing for compliments OR setting myself up for feeling defensive of criticism. But I want to hear supportive things! Especially since I have to play all the bad guys! I think it's helped me to ask my players more direct questions 1:1 outside of session: "I know that the relic being tied to your backstory must have been a surprise! Are surprises like that okay for you?" "Oh I liked that! It made my character feel important. Actually I kind of wish that moment wasn't immediately overshadowed by the combat right afterward..." So, to solicit feedback, I actually do the
opposite of asking open-ended questions. I think it helps draw focus while still opening up the conversation to what else might be on their mind.
Second, I can relate to the feeling of players not contributing enough or responding enough to make my effort feel worthwhile. I had one bit of feedback that really ticked me off... in a non-game social setting, one of my players was telling me that his
other DM does this "really cool thing" of using characters' personality traits and bonds and flaws (these are codified in 5e) to drive story. I had to slow-blink at him for a moment and wanted to tell him, "Yeah... if you think I'm not doing that, it's because you never filled in that part of your sheet, even after I prompted you multiple times and finally gave up." It certainly hurt my feelings, because I realize that his failing to meet my expectations turned into my failing to meet his expectations--and somehow this other DM had managed to motivate him to do this, AND he didn't even realize that's what had happened! Instead of giving the defensive response, I said "I'd love to see the sheet you have for that other game, and maybe we can use it as inspiration to fill in those sections on your sheet in our game." Yes, being the DM almost always involves being the grown-up in the room.
Third, my most depleting DM struggle is having to be the Gracious Host (see also: grown up in the room). As analogy, if I'm hosting a party to watch sports, and I ask people to bring beer to go with the food I've prepared... and then they all show up without beer, pick a little bit at the food, and ignore the TV, I'd feel anxious about my abilities as a host. Maybe I ask "So.. is everyone enjoying themselves?" A few shrug, and one says "Well we were hoping you'd have cocaine and dance music." Certainly I shouldn't feel I've done anything
wrong not having those things. But, do I perhaps consider altering my plans to meet their expectations? Maybe I say no to cocaine and yes to dance music? Turn off the sports and keep the food available, because they're going to need it. Were they being shitty guests? YES. Did I throw out everything I prepared? Never. I figure out what's most important to me (the food) and what's most important to them (dancing). Sadly, Gracious Hosts don't get the opportunity to be truly selfish, but you do get to set the rules!
Finally, I feel that Johnn's foundational materials actually help me to address these issues! Yes, we're writing adventures, but we're starting really basic: understanding our players' motivations (not just their characters!), understanding our own priorities, and of course, discussing those as a community. As
@ExileInParadise says, the fact that your players keep showing up is the first thing you need to know you're doing something right. If you feel up to it, you may even let them know that you're involved in a workshopping process and will be seeking specific feedback from them. The fact that you're excited about revisiting this world that you enjoyed many years ago is the second point in favor of keeping at it!