STR tax loophole with a 2nd home loan

[Pretty Khare]

If I buy a vacation home using a 2nd home loan and rent it as an AirBNB when I am not using it, can I still do a cost segregation study to accelerate depreciation and offset losses against my W2 income if I follow the rules of STR tax loophole (I.e., the average stay in the house is less than 7 days, I manage the AirBnB myself, and spend 100 hours or more a year and more time than any other person/entity on managing my AirBnB business)?

My CPA is saying I cannot offset accelerated depreciation losses against my w2 income as I have a 2nd home loan, but I heard in Brandon Hall’s podcast that IRS has a different definition of a 2nd home than what is used for mortgage.

PS: I think I need a better CPA. Any recommendations?