You make some good points here.
1. I stated index in this post (whoops); luckily I called it a list on the website.
2. Partly, in seeking an income strategy, that seemed important to me. Also, frankly, it allowed me to limit the scope of my dataset a bit. Maybe I should go back to the drawing board and include quarterly stocks as well, though.
3. I'll look into it
I'll jump ahead and answer your last question as it's relevant to the others: I'm using Polygon.io's API to pull financial data. I too have noticed that the data can be unreliable, repeats, and has many records missing certain data. I've sanitized that data on my backend, checking for and removing duplicates, as well as only displaying historical records with adequate data. Beyond that, I'm not sure how to improve the quality.
4. What about dividend reinvesting? Can't you avoid taxes if you do that?
5. Is that also true with leveraged funds? It seems like many of these high yield dividend stocks are in that category.
6. Interesting, I'll look into that.
Hope I responded to all of these points adequately. I appreciate the thoughtful and intelligent answer. I'm still not sure (and need to do more research) on whether such a dividend strategy is useless. It seems like reinvesting could provide good returns as a strategy--when the stock dips, so long as the payout is constant, you simply get more income. Maybe I'm missing something, though.