The most awesome musicians in all the world have songs, licks, and solos they mess up on, that they can't play or sing well - that they're developing. But guess what: you never hear them messing up on an album or concert. Why? Because they leave the stuff they can't do off the recording and simplify the solo or change the key at the concert to something they can do. Classical musicians take the edge off the tempo, leave a section. That doesn't mean these amazing musicians are losers, it means they understand that their job is to make a performance that's at the top of their successful ability, something they can nail. You'll never hear the stuff they can't do. That what all audiences consider great, a performance at the top of your ability , but well done. So that means it's right and normal for you to make these kinds of adjustments to your music to bring the piece well into your abilities, so you can knock it out of the park. So make changes in the short term to your pieces to bring your performance up to excellent, 110% AS you work on growing your abilities in the long term, so you can add the things you took out.
Great instruments and equipment are very inspiring. When you're discouraged, go get something new for your music. It'll encourage you.