I dealt with evictions, unexpected repairs, and the ups and downs of tenant relationships—but I also made huge strides in improving the property’s value and financial performance.

I don't know about your idea of maths but to me that says Midwest performs at 2X of CA. 

So if I am looking at an asset as a 10 year play - I look more at the location, schools and how has this market performed in the past excluding covid and 2008 which were extenuating circumstances.Reality is right now shorter term plays do not work based on numbers and cost of financing - we went through this same thing in 2001-2004ish timeframe where properties would appreciate 2-3% per year and after buying costs and closing costs - you were not making money on assets unless you performed the labor or found a really good deal.this is how real estate "typically" is - which is why everyone always says location location location - because after a decent holding period, you will win.

But, they have ZERO liability for the performance of that tenant.Second, 97%+ have no idea on how to screen a tenant, other than income = 3x rent and a credit score.

However the property is not performing and it’s affecting our personal lives now.

All things being equal on the asset side, the operation and systems put in place will make or break the performance of the investment but at this point that has almost nothing to do with real estate. 

The return on equity is probably very low considering they are paid off so maybe explore refinancing or selling the lowest performing one(s) or your biggest headaches to reinvest in more lucrative deals.I noticed you also used a metric of number of rentals to attain your goal rather than $$$/month.

Quote from @Benjamin Finney: Chris, interesting niche on non-performing mortgages/ rtl's.

Some towns require a nightly online form to be filled out for any non-residents who are parking their cars (this is easily automated from an operational standpoint).As the MTR market becomes saturated over time, those who have separated themselves from the rest of the "competition" will continue to perform well by having an outstanding listing and all the MTR-specific amenities.

Always perform thorough market research and verify the numbers on any property you consider.