My current strategy is to maximise equity over cash. 

Also did you grow only through cash flow or did you take investor capital to reach where you are today? 

Even with conventional loans, unless you've been self-employed less than two years or don't report your income, it's the same as someone with W-2 employment We lenders just cash-flow you differently.

Purchase price: $650,000 Cash invested: $65,000 STR in Black Hawk CO

I need to double check, but I believe TN is in the 13% range with state and local.Then several areas basically tripled property taxes practically overnight in a massive cash grab.

Other option would be her doing a cash out refinance on her home and using that money to purchase with cash.  

Purchase price: $800,000 Cash invested: $80,000 Primary residence with an ADU What made you interested in investing in this type of deal?

Also know that the housing market might not go up as quickly as you like...but honestly as long as it cash flows when you move out that is okay...I recommend saving up at least 6 months' worth of rents and having it cash flow at least $300 a month before moving out of the property.

Purchase price: $999,950 Cash invested: $2,000 Our Good Neighbor Realty Office in Denver!

I'm open to other creative methods such as Cash App, Paypal, etc. ... but I believe that they charge for automatic ACH payments.