Business loans typically won't let you purchase a property if you read the fine print.

I bought a 3/2.00 home in Tampa, FL in April 2022 for $245k at a 4.75% interest rate, I still owe $210K on the loan, my RE agent thinks it could sell for $280k ($70k in equity).

If I got a home equity loan for Property 1 and used the proceeds as downpayment for Property 2 and then got a 2nd loan for the remaining 75% purchase price for Property 2, when I sell Property 2, can I use the Property 1 loan as part of the cost basis for computing Property 2 capital gains?

Unlike a mortgage the interest on your loan will not be tax deductible.

That being said, with interest rates being higher now, I may not be able to find a turnkey property that makes financial sense.  

Quote from @Josh Lansberry: You will hear a lot of people bad-mouth him, but Dave Ramsey can teach you how to get financially savvy real quick.

So it's a loan....You just detailed a loan. 

You'll need more capital and most will require a personal guarantee and personal financial backing. 

I'm curious why you want a HELOC instead of a conventional loan in the first position.

Since you will be renting it out you should get a conventional loan.