Purely anecdotal, as I haven't actually researched the market, but feels like in my FB groups this one was hot during covid and now people are panicking as supply has gone way up there and demand returning back to normal.

Getting your duplex by being an owner occupant will be far easier that doing it in reverse as a pure investment.  

Will it be a pure cash deal?

It's purely personal, of course, but for me I'd be OK with lower cash flow in exchange for a greater and growing equity stake, since I have a longer buy-and-hold horizon.

If this is purely a financial decision, then see what the cost/income analysis for one versus two.

We recently bought our 39th house, some of which were pure flips, some were fix and flips, and many have been long term holds. 

Now if LA were to crash again, I'd certainly pick something up purely for the appreciation option...and preferably with as little of a mortgage as possible. 

You can't.. so what .. it is pure luck then.EXACTLY!!

If you’re looking for a pure rental you need to go north or west.

The IRS really does not like it when something is done purely to minimize taxes (there has to be a business purpose and economic substance).