Both Xebeks and Galliots were upgrades to the Galley and the Fluyt.
Fluyt is from the 16th century, while the Galliot is from the 17th to the 19th.
The Galley is also an ancient ship, even by tjhe 16th century, and the Xebec was a more advanced fast ship than the Galley (which was historically a slow ship, unlike in the game)
" Xebecs were ships similar to galleys primarily used by Barbary pirates, which have both lateen sails and oars for propulsion. Early xebecs had two masts while later ships had three. Xebecs featured a distinctive hull with pronounced overhanging bow and stern,[1] and rarely displaced more than 200 tons, making them slightly smaller and with slightly fewer guns than frigates of the period."