Glad you recognize this fact. Love explaining the SPY as "rank public equities by revenue, take the top 500, then weight by market capitalization".

Starting an ETF is highly regulated, this differs in that these algorithms just manage your money interfacing with the public market rather than moving in ETF. Less regulation, but encounters tax implications (hence the less frequent trading of these models) among other things.

If we're talking about long term investment than dollar cost averaging is about the same as lump sum on January 1st.

As for starting an ETF... Well minimal capital requirement is 100k, to launch it's probably 300k total investment. Then there is a lot of legal requirements and obligations. Whole process is at least 6 months

I guess it depends on what's your goal. Some brokerages let you create a bundle of stocks and share them publicly or privately. Which is sound more like what you want.

Doesn't the research support time in market producing better value over cost dollar averaging?

I'm not sure - I guess it would depend on the volatility.