You can only deduct mortgage interest on the first $750,000 of the outstanding balance on SCH A for a mortgage loan established after Dec 15, 2017. That's it.
See IRS Pub 936, "Home Acquisition Debt Limit" on page 10 at https://www.irs.gov/pub/irs-pdf/p936.pdf#en_US_2020_publink1000229992
