I've been using AAVE to short BTC for a few months now.
Love the fact that you get to basically adjust the leverage yourself by depositing USDC/DAI and borrowing BTC and then swapping it to USDC/DAI and re-depositing and borrow more BTC and rinse and repeat until you get the desired level of leverage.
It's on polygon chain to save fees.
Plus I get paid interest to hold this short position as USDC/DAI has higher interest paid as deposit vs the BTC on borrow.