I can relate to this. I look back on all of those projects and I do see the basis of the learnings that really moved me forward in terms of technical skill and reasoning. School was horrible for teaching practical knowledge and if I had simply followed the patterns that were applied at work, I would be no better than I was 15 years ago.

So yes, probably some level of time wasted, but best to take some of the learnings from that and count a few victories however small.