https://flyp.me/en/

i've used them before, no complaints. instant and no account registration.

i would avoid swapping to monero and directly back to bitcoin. to make it harder to trace, you should layer in a few monero transactions before exchanging for bitcoin again. that way, not even flyp.me will recognize your inputs.

i know that exodus use(d) shapeshift for their built-in exchange, and that shapeshift started requiring KYC. i'm not sure how that affected things.