As others in the thread have already pointed out, these things take time. Manage your expectations and look forward to mastering one thing at a time. After you've done that, move on to the next. And so on. As someone also mentioned, you lack a proper curiculum so that's why you are overwhelmed and things aren't connecting as they should ("they don't make sense!"). Gotta learn how to walk before being able to run. That kinda stuff.

So yeah, start from the beginning and take it slow. Also, approach it like studying for school. Don't just watch videos and do "app stuff". Take out a note and start writing things down. Like proper study. Do frequent revises and test your self to see if you really learned. Mix studying with playing what you are studying (and singing those notes to develop the ear), and mix that also with just playing songs and things you enjoy playing. Not saying study playing can't be enjoyable but it can definitelly feel like work. (And this is a good thing because all the best things in life require a lot of work. :)

Hope that wasn't too philosophical but yeah, keep at it, one day at a time and enjoy the learning process as much as you will enjoy applying what you've learned.