I would only recommend a mortgage because they can be obtained at preposterous durations (30 years) so that equity can outpace the interest as Bitcoin

You could consider unsecured only if you’re willing to potentially default and wreck your credit score (because you already have a mortgage and won’t be borrowing again) and pay 40-50 cents on the dollar to keep from getting sued

In all, I wouldn’t risk it. Better to stay humble, stack sats, and produce more than you consume for as long as possible