I’ve been to Xlendi Bay several times, which was nice 20yrs ago. My mum goes out every year to visit relatives that spend the summer there and she still loves it. Laid back, nice people There was a Hotel on the beach called St Patricks but we always stayed in Apartments. As above, renting a car would be advisable. We travelled around the Island a fair bit and I snorkelled everywhere, while its not outstanding, I saw some cool things like Octopus and small sharks.
Edit- you’ve got me thinking about revisiting Xlendi again, cheers :-)