Save more for a maybe a year and then get a HELOC if possible and buy the second one.

To the OP: I wouldn't sink $500k into one building and be careful about over leveraging (taking out equity with re-finances or HELOCs), especially if you want to quit your insurance job. 

And using debt, even a 1st position heloc at <50% LTV can and will notify you of this 'for your records'...

Used a HELOC for the downpayment and Hard Money Lender for purchase and rehab How did you add value to the deal?

You can hypothecate collateral from one person/entity for use by another person/entity, but you might want to borrow the money as a home equity loan (fixed payments and term...one time funding) or a home equity line of credit (HELOC).

I am considering taking out a HELOC on this property to purchase another property closer to my primary residence.

I used hard money and HELOC's on other properties How did you add value to the deal?

Does HELOC and other home equity financing methods work in the current high interest rate environment?

I also cannot go HELOC route because the LTV does not meet lender requirements.

I get around that by using my Credit card or HELOC then going by the Credit Union later to transfer funds.Hope this helps.