BTC borrowing math question...straining my brain here

This is straining my IQ; can you help with a bit of math? Related to these bitcoin-collateralized loans and a good strategy for me in a lucky year.

I have been putting my monthly home taxes and insurance savings in BTC (at a rate where if I was just saving cash I would have enough after the 12 months...I save it myself because my mortgage is paid off) and obviously have done quite well this year.

Last year I sold from this account for what I paid for the coin as the price had not changed much from my average buy price --- however, this year as you might guess, has been a bit different!

I obviously have quite a multiple of what I put into it, and now I am hearing about bitcoin-collateral loans. About how "the rich borrow money against assets instead of selling it" to not owe capital gains -- and moreover take a deduction from interest paid.

That said, I read the terms from, for example, unchained-capital.com (as it seems one of the only that does not risk your coins lending them, despite the higher interest rate...ok by me) it seems to me I would need to do the following:

On a 10,000 loan --

Pay out ~$91 dollars per month in interest payments. I would pay out of my own monthly income.

Balloon payment of the $10,000 after lets say 12 months.

And now -- this is what I don't get...I don't want to pay capital gains. So I would just hold back the $10k/12 = $833 per month in cash (?) and pay them the cash when the loan is due, hold onto the original bitcoin...

...but NOT buy more bitcoin with that monthly $833 (?) as I have been doing? Because at that point I would need the cash to pay them, but selling Bitcoin to pay the balloon would incur the tax event I was looking to avoid in the first place.

I'd hate to miss more sweet gains not buying -- but I wish to understand the strategy here, and this quickly gets out of hand for me. Any tips or math to offer here? A good plan?

I am very grateful for having had this magic savings account, and if I can preserve value over time like this, that would be absolutely super.