Pay down securities backed line of credit (6.2% variable) or invest (VTI)?

What to do, buy more index ETF (VTI) or pay down SBLOC?
Couple yrs ago I took out loan for home downpayment when rate was still low, ~1.85%. As variable rate increased I started paying it down. Now rate is coming down ~6.2% (SOFR +1.55%). This is my only "high" interest debt.

I'm currently only putting any dividends/distributions from brokerage towards SBLOC instead of reinvesting in VTI.

At what rate would you stop paying and let the SBLOC interest accrue?

Liquidity isnt an issue. Not at all worried about a maintenance call on the account. Retirement is fully funded.

Wife and I have agreed to stop paying if rate hits 6% but I'm thinking we might be acting too conservative. We once paid of a 5.5% mortgage and missed years of market gains and dont want to repeat but this time could be different.