Goldman advised investors to "Buy" Tesla (i.e. their "opinion" is that the stock is a good investment and should increase in price - quotes because of a well-documented positive bias of sell-side analysts) just before underwriting Tesla's offering (i.e. taking fees for successfully selling all new shares).

Goldman Researchers advised investors while Goldman Investment Bankers underwrote a deal. These guys (and gals) aren't standing around a water cooler chatting about their work with each other for exactly this reason. It's highly unethical, and illegal to share this sort of information before it's public.

You mean unethical in the same way that Goldman investment advisors were trying to make their clients buy instruments that Goldman traders were desperate to sell during the financial crisis?!