Can I long USD/BTC instead of shorting BTC/USD? Let's say that I think that bitcoin has hit a peak. I want to short bitcoin, but in a far less risky way. In order to do this, I want to go long on USD/BTC. Let's say (as an example) that I longed this pair when Bitcoin was $13,250 (on the dropping side, I set that as strike price), and sold it when it was $8,000 and going up. I would have made a 65% return as opposed to a USD/BTC short of just under 40%. I want to do this to be able to make a higher profit during a bear market. I feel that this is a good idea.

The question is, to clarify: can I long the USD/BTC pair? This pair is equal to one divided by the USD price for one bitcoin. I think it is good because it offers an alternative to shorting, one with a theoretically unlimited upside and a limited downside. If one bought $250 worth of bitcoin at $100 and sold the position at $6,000 in the beginning of November of 2017 or 2018, it would have brought $4.50 as opposed to a theoretical owed amount of over $14,000.

As a commenting individual in the comments said, this move could have theoretically brought (and maybe has brought) very high returns. Even going back 1-2 years ago (roughly speaking, as of writing), such a move timed at the right time could have brought 500% or more returns depending on how good timing the trader had.
Long USD/BTC is the inverse of short USD/BTC, which is identical to short BTC/USD.