@Natalie Kolodij Further research shows that you are right.
Base on the IRS link that you posted, second example clear states that interest is not deductible.
"example 2: In January 2018, a taxpayer takes out a $500,000 mortgage to purchase a main home. The loan is secured by the main home. In February 2018, the taxpayer takes out a $250,000 loan to purchase a vacation home. The loan is secured by the vacation home. Because the total amount of both mortgages does not exceed $750,000, all of the interest paid on both mortgages is deductible. However, if the taxpayer took out a $250,000 home equity loan on the main home to purchase the vacation home, then the interest on the home equity loan would not be deductible.
https://www.irs.gov/newsroom/interest-on-home-equity-loans-often-still-deductible-under-new-law
This is a bit confusing, but...
If you dive into Interest tracing rule, any debt for investment interest seems to allow tax deduction. In other words, you can't just deduct your HELOC interest, but if you justify that the HELOC was used for investment interest (i.e buying a investment property) then you can deduct the interest.
https://roundtablewealth.com/resources/mortgage-interest-tracing-rules/
Perhaps, I asked the wrong question or I need a new accountant. Thanks for your input.
JK