HELOCs - Calculator tool, Relinquished Debt with 1031

[Walchli Donna]

Hello All. Three part question regarding my HELOC. TIA for any guidance and considerations.

1) I'm having difficulty finding a HELOC amortization calculator. Anyone have a resource for one that I can use?

2) I have two LTR properties: CO sfh and FL twnhs. The CO 1st position mortgage was fully paid off and in 11/2021 I opened a $200K HELOC, Borrow Terms are 5yr draw/15yr payoff at 3.99%. I borrowed the full $200K on this HELOC to purchase my FL investment property Nov 2022. I live in FL and self-manage this property but have a Property Manager for my CO property. I've been paying aggressively to free up funds to borrow at the 3.99% as needed. The current balance is approx. $160K and I have roughly 15 months remaining on the 5yr borrow period. With the economy and market as they are, should I continue aggressively paying down the HELOC to potentially borrow against again or should I just pay the Interest Only (IO) payments and seek other funding at the current day higher interest rates?

3)  So the FL townhouse is secured by the CO property.  I'd like to sell my CO property and do a 1031 Exchange for a local FL property but I've been cautioned by members in the local investment clubs about potential Relinquished Debt consequences.  I can't seem to find more info on this.