All this being said, a mutual fund based on an index like the S&P 500 is more diversified, and therefore less risky than any single equity. If you are afraid of "gambling" in the stock market, just park your money in a low cost passive index fund, and let it grow.
Yes and no.  A NASDAQ ETF right now is mostly exposed to Facebook, Amazon, Apple, Netflix, Microsoft and Google.  All of those stocks have insane P/E ratios.   They're actually more prone to shock than something boring like 3M. But A diversified index fund covering lots of boring stocks is largely bombproof.  A 3X inverse ETF is based on an index and is about as stable as plutonium.  Either way, an ETF based on a long portfolio of dividend - paying stocks will pay a dividend.  In many cases, particularly where the market is at, the dividend performance outstrips the appreciation performance.
Boy.  I don't know that I can even say anything useful.  I don't know that anybody can.  My personal strategy is to find a lazy portfolio, backtest it, make sure I understand the way it moves and make sure I think it'll fare okay from what I understand of the geopolitical climate for the amount of time I expect to hold it.   Which basically says I'm macro AF, and that I disregard everything but fundamentals.  It's probably about as conservative as you can go and I've definitely given up some gains that way.  But it's what I understand, and what makes me feel like I have a reasonable sense of cause and effect.   I think the stock market is deeply overvalued and headed for a correction.  From a macro sense, from a fundamental sense, a Russell 3000 ETF does not strike me as a good value at the moment.  But that's my take, my tea leaves, my entrails, not yours.