I want a crypto index fund.

It should be an index fund of the top X coins in terms of market cap, weighted by market cap. Perhaps use coinmarketcap.com to recalculate. I would be happy if X was any number over about 10. Now, this might catch some scams, but it will be self correcting. The primary advantage is the same advantage of index stock funds over actively managed stock funds.

Details tbd include whether the fund rebalances every day or every week or whatever, where to buy the coins that it would hold and where and how to trade to maintain the index-required holding percentages.

I have been looking/reading/watching for several weeks now and haven't found a passive coin index fund. It should exist and I would invest if it existed.

What do you think?

Edit: It appears cryptomover's index may be exactly what I want, but I think I read that U.S. investors are excluded.