Wealth is wealth. Market valuations are based on profits of the underlying companies. Some companies are more sensitive to recessions than others, or have exposures to different economies in different countries.
Theoretically, a diversified global portfolio is better than just investing in the US. But I haven't looked at the risk-adjusted returns in a long time....my suspicion is the US is higher.
I don't know of an asset class that's a good investment now. Been that way for a while, even while the markets were going up and up. My advice is mainly pay down any debt with higher than 5-6% interest rates, dollar-cost average into the market, and re-balance annually. Buy a house, if you haven't already.