Great topic! I spent 5 years as a Stock Broker working for one of the large firms. I learned a great deal from being an Apprentice to a team where the average age was 73. They were moving stocks long before the age of the computer. I would often come into the office all emotional about whatever the latest news cycle was and today's dip or surge in the market. They always told me the same thing. "This too shall pass". This I know to be true: You cannot time the market.
I now teach Business and Economics at a college level. They do not teach this in the textbooks but I believe that we cannot predict the market because the market is about human behavior. Human behavior is impossible to reliably predict with economic models.
All of that is to say that buy and hold is the only strategy that consistently produces results. What you buy and how long you hold is a matter of your risk tolerance, your goals, and your financial situation. If you cannot afford to lose it then never invest it. By the time a news story hits, it is too late to invest based on that information.
Pay off all debt. That is your best shot at having a stable financial future. Investing is of no value if you are making 6% in your mutual fund but your credit card is hitting you for 15%. Once you are debt free then it is time for a cash emergency fund of 90 days living expenses then real estate is a smart first choice, as in a primary home, not for speculation.
After those things are out of the way then long term mutual funds are smart. American Funds Growth and Income was a huge seller for me when I worked on Wall Street. Gold, not paper gold, the real thing, is good for a hedge against inflation. Quality firearms seem to hold value nicely.
It is too early for us to see the complete set of consequences from an economic shut down where 40 million people are out of work. These economic situations are unprecedented. We have no models for this. The experts I follow predict a brief rise into the next election then a sharp decline. Personally, I am keeping my assets in cash in anticipation of buying opportunities.
I hope that helps.