It sounds like you would feel a lot more comfortable with a structured learning program from a pro teacher. I know Justin Johnson has courses and there are at least half a dozen more who offer books/lessons to take you from raw beginner to someone who is able to play at least a dozen or more songs with reasonable competence.
You are accustomed to checking for lessons on tips on YouTube. I suggest if you want to keep learning for free you just concentrate on all the beginner level lessons. Keep going back to these until you can do these with no problems.
Once you've gotten all the beginner slide guitar lessons under control, you should start working on the beginner cbg lessons with chords. You're going to have to know the 1,4 and 5 chord progressions which are the backbone of blues songs, as well as being able to play the chords. That of course entails being able to change chords quickly and be able to take your movable chord shapes and go up and down the neck smoothly and cleanly with them.
I've been learning for about a year and a half, and my progress has been slow because of not putting enough time into practicing and learning. I've devoted most of my free time to building, but like you I have wanted to get good enough on a 3-string to be able to show off my builds by playing them.
Bottom line is you just have to put in the time to learn the music knowledge as well as additional time for learning all the most-important chord shapes and be able to go to whatever chord you need without fumbling and play it cleanly. The good thing is it isn't rocket science, you just have to put in the hours.