Atomic swaps are being used by many DEX's and dapps to trade bitcoin and ETH like coins with each other --it's not impossible.
Sure it's possible, but I don't know of a usable enough service for atomic swap.
I found only AtomicDEX, but they don't good enougth, they allow use for trade only their own wallet.
U say many, so give me links where i can swap BTC to ETH by atomic swap.