Interest on lending, and trading fees from liquidity pools. During a bear market in crypto certainly these yields will decline.

The 2 sources I mentioned above are essentially flows that accrue during the bull markets. It's not magic, when people want to long assets they borrow stables. If you lend into these markets you'll get the yield. With liquidity pools you can get some transaction fees even during market volatility and draw-downs, in the short term at least.

Am I to believe people are paying > 20% interest to borrow crypto ?

I hope not, or else I'm missing out on a lucrative counter-position.

No