All I know is after a quarter of a century, I would have done almost as well just stuffing it in a pillowcase. Which is still an option, I suppose!
Just look at what those recommended index funds have done over the years. It seems the objective of “managed” money managers is to feed off of your labor and savings “managing” any gain from your pockets to theirs. That also includes fund managers feeding at the trough.
You can’t get much more diverse than an index fund and that does not include the dow, too narrow.
Going forward is the only real factor. Avoid paralysis if what you are doing is underperforming and something else has a better track record. You probably don’t have the experience, temperment, time or resources of market intel to be a trader. I surely don’t
I can guarantee that if you keep doing the same as you have been the results will be the same as they have been.