TL;DR - you dont know math. See part 2 and wait for part 3.
I read the post before I commented.
I don't know anything about you, but I'd be willing to bet that you've obviously never worked in professional financial services.
Your 2 points in the "what should I do instead?" Section are laughably stupid...
  1. Point 1 is quite literally pitching exactly DCA, you're just pretending it's something new other than DCA, for your narrative.
  2. Point 2 is dumb and reveals your ignorance about the finance industry.