I've been tinkering around with investment strategies for the past 40 years or so, and have found that there is no silver bullet. But you sure can waste a lot of time looking for one.
You have enough time (by which I mean 10+ years) to go all-out on equities. I have a single investment vehicle.
VWRL: Vanguard FTSE All-world ETF
-Vanguard charges low fees, and is pretty reliable
-This fund contains thousands of constituents, from all around the world, providing diversification unattainable by other means
-The fund displays pretty steady growth, with moderate volatility.
-It a "distributor", offering a small 2% dividend, which is useful for paying fund manager fees, and perhaps incrementally building up an interest earning cash "pillow".
People say that the USA is overweighted, at 60-65%, in such global indices. But consider:
The capitalisation of all the companies and markets in the world is reassessed every day, by millions of investors and traders, executing billions of transactions. You must be very confident of your own uniquely superior analysis skills to believe that the global consensus is wrong and that you are right.
Having said that, if and when US market dominance declines, then its weight in the ETF will be correspondingly and automatically reduced by Vanguard during its quarterly rebalancing procedure. No need to intervene personally.
Nobody can beat the market. If that sounds a bit dramatic, read this article:
Calpers and Bridgewater
which shows that Calpers - a huge public employee pension find, and Bridgewater - a gargantuan hedge fund, cannot beat the returns generated by a low cost, passive, super-diversified ETF.