What we should know is that investing in cryptocurrencies is high risk, and even with our own capital, we have to think about the risks we will face, let alone do so with a loan.
Making a loan is not the best way and even if you do, you must really have the ability and a good plan and also the trust to get the benefits and pay off the loan according to the agreement.
I personally do not recommend that you borrow to invest in crypto, and my advice is better to sacrifice something of value to sell and for investment capital and if everything is beyond your expectations, you have no burden to replace your loan.
and I think there must be many who do things like that and if the results are profitable you can buy back what you have sacrificed and enjoy the benefits as you like.
I agree with your point about how you should handled this business, taking loan is not recommended due to high volatility nature of crypto.
Unless you really have established skills that you can use to work with lesser risk, there are people who dedicated their time to understand the deeper side of this industry, they are capable of anticipating the next run and most of the time they managed to earn decently.
Though still not an assurance but with such knowledge the chance to repay your loan is possible if you have sets of skills and good money managements.