This is one of the primary advantages of some slight diversification in your portfolio.

What I'm interested in is diversification and passive income.

You have to start somewhere, but a single house doesn't provide enough diversification, financed or not. 

Diversification: Owning a duplex diversifies your real estate investment by having two income-producing units in one property.

Considerations may include the balance between diversification and quality opportunities, risk tolerance, market conditions, and the potential benefits of progressively scaling down the investment size.For those experienced in real estate syndication or investment theory, what insights can you share on the concept of progressive scaling and its impact on portfolio optimization?

I'm a believer of diversification, so being invested in real property AND syndications/funds. 

Another reason I like syndications is diversification. 

Syndication, pooling funds for real estate investment, is an option with benefits like diversification but comes with risks like illiquidity and reliance on the syndicator's expertise.

**Crypto IRAs**: SDIRAs enable investment in a diverse array of assets, including cryptocurrencies like Bitcoin and Ethereum, gaining popularity for their portfolio diversification and inflation hedge potential.2.

Yes oil and gas make a huge part of our GDP, in fact, the last data I've seen suggests it might be even higher than 25% (29%) and this is a major point of concern for me, this causes our market to be much more cyclical, however, look at the diversification that has been happening in the chart below and this continues to trend in the same direction, we still have good years of oil (and especially natural gas) demand ahead, I would be much more concern if we were not diversifying but we are, especially over the last few past years.