I do not know if this can be a monero-related question. I have the following one: what's the main difference (or the differences) between Atomic Swap and Bisq? Bisq seems a P2P market that connects buyer and seller, while Atomic swap integrates directly into blockchain.
First one needs to disnguish between a marketplace (where makers / takers advertise trades) and how a trade is to be executed (the exchange protocol for a trade).
Bisq is a P2P marketplace which also defines an exchange protocol. There is no centralized entity involved in advertising trades (for makers or takers). When it comes to executing a trade, if there's a dispute, an arbitrator (a 3rd party) gets involved. It's akin to meeting someone in a public place to swap USD for GBP and asking a random stranger to observe (to help in case of a dispute).
An atomic swap is only an exchange protocol (any marketplace is separate). This exchange protocol is a mechanism to convert one cryptocurrency for another without needing a 3rd party arbitrator in the case of a dispute. This is because the swap occurs using a contract derived from the respective blockchains. In other words, the swap only completes if both participants actually pay each other the agreed upon amounts.