Here’s something you can try: take the song ideas you’ve discarded in the past — including melodies, chord progressions, and beats — and resurrect them. Give them another chance. See if they contain anything useful. Perhaps they found themselves on the receiving end of your past frustrations. See if there is anything that can be resurrected into another creative endeavor.
One of the benefits of using a notepad, manual typewriter, or another physical medium is the physical record that you leave behind. Perhaps you crossed out some lyrics or chords, but at least you can see what you crossed out, assuming you didn’t toss it in the trash or burn it. Take another look with a fresh set of eyes and find out if you perceive the essence of the original idea that inspired you to write it in the first place.
Ideas come to us all the time. Sometimes we judge them or talk ourselves out of them. And sometimes these ideas come to us when we have made up our minds that something else should be produced, rather than what came to us in a flash of insight. Revisit them and see if you can understand why you thought they were a good idea in the first place. You may be surprised that you ever discarded them at all.