I'm biased, but I don't think conventional is the best product if you are doing a rehab. You mention using hard money for the rehab, which, in combination with a conventional loan, would require you to be in high-interest rates for a year until you can cash out refinance. With some DSCR loans, you can cash out refinance in as little as three months, and the rest you need 6 months. With conventional, this would mean you would be paying 6-9 months of high-interest rate debt before you can pull cash out.
If you decide not to do a DSCR loan, the second home loan is a popular option, but there are lots of drawbacks for investors as it is really a product made for regular home buyers. With second home loans, the mortgage must be for one unit (I do a lot of 2-4 unit STRs), the property must not be rented for more than 180 days out of the year (limits revenue), must function reasonably as a second home (usually limits out of state investing), rental income will not qualify as stable monthly income (projected AirDNA does not play into your DTI). There are a couple others, but you can check the Freddie guidelines yourself:
https://guide.freddiemac.com/app/guide/section/4201.15
For AirBnBRRRRs, I suggest structuring with a hard money loan to purchase and rehab the property and then doing a DSCR refinance using AirDNA projections. This gives you the most flexibility with investment properties. Also if the prepayment and rates are a deal killer, you can always structure the deal with no prepayment or buy down the rate to the 6's.