After 1 or 2 failed side projects, you should have learned roughly 80% of what you need to know. A few more might get you the next 20%, but 17 failed projects is likely not teaching you anything you couldn’t have learned before, you’re just wasting time at that point.
The optimal amount of failures before a successful project is probably about 3. After that, you need to seriously consider that maybe you just don’t have what it takes and move on. Otherwise you spend your whole life chasing something that will probably never happen, and avoiding better opportunities.