I always hear the “Cap ex of 10% rule” but have yet to hear any alternatives.

Considering your goal of house hacking a duplex, while FHA loans are common for first-timers, there are alternative financing options to explore:Conventional Loans: Need more credit and down payment, but offer flexibility. 203K Loans: Ideal for fixer-upper duplexes, bundling purchase and renovation costs.VA Loans: Great for vets—no down payment, competitive rates, and no mortgage insurance.Portfolio Loans: Private lenders, good for unconventional income or credit histories.Hard Money Loans: Quick, high-interest, good for investments or major renovations.With $30,000, mix it up—use it for a down payment, maybe pair with a conventional or FHA loan.

We completed over 20 million in seller financed/carry back/ maser lease option deals.It's back on the menu, and only going to get even more popular as debt becomes more difficult.

As a viable alternative to explore with a lender, consider the advantages of a 5% down conventional loan, or even less for qualifying first-time homebuyers, which often comes with less stringent property condition requirements. 

My partner's family owns an STR, free and clear, worth between 1.8-2 million in a popular vacation destination.

What's popular and saleable in one place isn't great in others.

As a landlord, that may prompt me to not renew the tenants lease hence they would have to seek alternative housing. 

True private money is a lot of times more expensive then alternative lending.

They are still a marketplace, but are working hard on transparency, data aggregation and reporting for buyers and trying to offer a nice alternative for investors who want to go the passive route.  

Cleveland is a very popular place for cash flow and some cities in Austin has done well in appreciation