The broker I'm working with, mentioned that any company can cancel any policy within 30 days of approval and that any premiums paid will be refunded, but my main concern is to get a policy in place for this property.

I suspect the new title examiner has found something in the chain of title or the execution and notarization of your deed that makes them unwilling to rely on it to issue your buyer a policy without exception for the concern(s). 

For your convenience, several self-addressed envelopes have been provided for your use.If you have any questions, comments, or concerns, please feel free to contact me between ##:## am to ##:## pm.

I am not a financial advisor and not giving financial advice.Reading through your post, your concern is risk management versus paying down debt, which might be a solution.1.  

Despite concerns over store closures, demand for retail space surged in the second quarter of 2024.

If you have concerns, don't buy. 

I’m concerned that holding this note may prevent me from closing on future deals due to DTI ratio.

Future risk is always a concern however never a value in an appraisal.  

I am contacting you to formally request validation of the alleged debt concerning this account and to inform you that I hereby dispute the validity of this debt.

Generally speaking, I have not seen underwriters look too deep into occupancy concerns related to second home vs investment property since Fannie/Freddie installed new LLPAs a couple years ago that make the pricing for each aligned in most cases.