With 2021 here and California just extending the noneviction moratorium till June 2021, is it a bad time to invest in buying a SFH or a duplex? I know this not a simple question but hoping to get some good advice.

I don't have any advice, but have been thinking about the same question myself.

@Bruce Umeck

That really depends on how you are going to buy the property. If you can buy vacant and screen and place new tenants, you could do just fine since there is little rental inventory available in many markets.  Contrary to popular belief, the eviction ban is not a blanket ban. You can still remove a tenant if you plan on making the property your primary residence when you purchase it. People can also be removed for other extreme circumstances such as being violent or breaking the law. 
if you decide to buy a purely investment property and want it vacant, try offering the seller a little extra and stipulating that he give cash for keys and deliver the property vacant.

There are still options in this market.

@Dustin Allen

In my opinion there are still good deals out here in Northern California. The Bay Area for example, only difference is a lot more money to purchase of course, at the same time if you buy a fixer upper below market value in descent to good areas, you could really make a good profits. Believe me there are tons of deals out here, have seen it happen over and over again. My 2 cents.