But what about the interest on a cash out refinance?

Just wanted to mention that the cash out refinance funds are not tax free forever.

I'd keep the rental and by no means refinance it to take cash out. 

What you describe sounds a little like a BRRRR (Buy Rehab Rent Refinance Repeat). 

Cash-Out Refinance – Refinancing one of your properties to pull out $30,000 in cash can be an option, though it may extend your loan term or increase your interest rate. 3.

I'm hesitant to give up my conventional loans on the next cash out refinance for DSCR loans.

If you are able to refinance out and remove your PMI that is probably the right play long term. 

It seems you're exploring Rehab Financial Group for your BRRR (Buy, Rehab, Rent, Refinance) strategy, which is great!

Now, the house that is about to refinance, I am thinking of turning into a MTR for traveling nurses, or other professionals as such.

I believe in putting in the work—1,000 hours of research, testing, and learning—before offering advice, and I’m excited to tap into the collective wisdom of this community to refine my approach.Here’s where my head is at: I’m considering strategies like short-term rentals (Airbnb) for higher cash flow, long-term rentals for steady income, or even creative options like house hacking or partnerships to stretch the funds further.