Sure. Use the Ren Bridge to lock Bitcoin into renBTC tokens on, say, Polygon. Deposit it into Curve's Ren pool on Polygon to get about 1% yield (currently) paid out in CRV. Withdraw renBTC and bridge them back when you're done.

There's a bunch of risks with this, the most prominent of which is WBTC token minted by BitGo, but see also the Curve interface hack. Saylor has said that he considers all risks like to be not worth it and therefore he just holds Bitcoin. That said, Fedimint's risk dwarfs all of this risk IMO.