Reason I ask is most investors are cheap and those who are not like to underwrite their own deals.

Being an agent isn't cheap.

Mortgage rates make buying a permanent residence painful and costly... 

Most of us saw record occupancy and nightly rates during the pandemic.

Rate will not be pretty... 

Here are some steps and resources that may help you confirm your numbers and conduct due diligence:Rental Income Analysis: To determine the possible rental income for your duplex, look up the rental rates for nearby homes that are comparable to yours.

- Am I able to do a mortgage assumption from personal to the LLC to avoid the balance being called and effectively keep the interest rate?

HMLs offer quick funding, but keep in mind the higher interest rates (8% to 18%) and shorter repayment terms (6-18 months).

Rates are too high, so borrowing costs are high.

Just a quick follow up to @Christie Gahan's comment: ** Yes, Long term capital gains are taxed at lower rates, but it isn't as simple as the first $500K of gains are taxed at 15% -- rather, the 15% bracket will account for your total income from all sources.