I tried THORswap, they charge you $20 fee. So much for their advertisement of having native BTC.
If you're using Ethereum, then you're being charged Ethereum transaction fees (which are pretty high). You're going to get that high of a fee regardless of what smart contract you're going to use.
ETH? I was using Native Rune for Native BTC and the fee was $20 i also tried with BNB USDT on THORswap and the same thing.