For a longer position you can short BTC/USDT perpetual futures using a margin account (Binance, FTX...)
For a little more involved position with a more secure counterparty you can short BTC/USD futures on the CME, you'll have to keep the contract expiration in mind though
The CME also offers options on futures contracts but there's barely any volume: https://www.cmegroup.com/trading/equity-index/us-index/bitco...
The simplest approaches would be an inverse ETF or a perpetual short position (only available on crypto exchanges afaik)
Elsewhere you can use Deribit: https://www.deribit.com/
Be careful—Deribit allows 100x leverage.
You might as well just go to the casino instead, your not going to get rich hedging crypto. Or buy CAD, buying USD tether against BTC won't work as they are both sliding.