Do I understand collateralizing debt?

Wanna see if I understand fully and explaining it back to someone helps me learn it. This is all one big question so take nothing as fact and correct me where in wrong.

SCENARIO

I have 1 BTC and it’s currently worth 50k. I want to buy a $40,000 Tesla.

SOLUTION

In most cases, people would sell the BTC to buy the car. The issue here is two fold - not only do you have to pay capital gains tax, but you’re also forced to liquidate your position in an appreciating asset. So you’d likely have to sell ~50k to end up with 40k after taxes. At the end of the day here, you’re walking away with just a Tesla.

A better option here would be to take a loan out against your BTC. So you’d use your 1 BTC as collateral and take a 40k loan out (over-collateralize a bit to prevent a partial auto-liquidation should the market pull back).

Let’s say the loan you take out come with 5% interest. You take the 40k loan and buy the car. No capital gains tax paid because you aren’t taxed when you spend a loan (or at least that’s my understanding).

Maybe I wait 6 months to pay the loan back. So I’d owe 40k + 2.5% interest = $41,000. However, during that 6 month span, my BTC appreciated from 50k to 60k. So pay 41k back and still hold 19k. So in this scenario, I walk with a Tesla +19k in BTC with no capital gains tax paid.

I know this is obviously super risky should the asset depreciate over those 6 months, but Let me know if im understanding the concept fully.