Ok, so if I'm trading you p2p on something like AgoraDesk or Bisq there isn't a special address on Bitcoin that is only used specifically for swaps, so I'm not really sure what you mean. It's just me sending Bitcoin from my bc1 address to your bc1 address. Many even offer PGP to communicate so AgoraDesk has no clue on any details about the txn, unless a dispute arises you can reveal your conversation, but that is very rare. I've never had to do that and been using both for years.

Even for atomic swaps, AFAIK, they might have metadata like a hash or something that might stand out more from average txns, but there is nothing that would tell you it was specifically for a Monero swap or a swap at all.

I know specifically for BasicSwapDEX they go a step further and use adaptor signatures and Scriptless Scripts that work off-chain to hide what little there metadata there even is, but I can't tell you the specific details on how it works off the top of my head.

Liquid only hides amounts. It's still traceable because senders and receivers aren't hidden. Custodial too.

https://tlu.tarilabs.com/cryptography/introduction-to-scriptless-scripts