There are some places that make you regret leaving so early. Ksamil is one of mine.
30 mins South of Saranda by car, Ksamil is her younger sister with less traffic, restaurants, and hotels, but more beautiful beaches and a slightly more hippy vibe.
For 3 days, all I did was go to the beach, at Guapa loca beach club and lounge for 6 hours, intermittently tanning till it gets too warm then dipping into the refreshing ocean. Its about 5-700 lek for 2 sun beds, and prices for food are roughly the same as you would pay at a restaurant in Sarande. 4 to 10 euros for Grilled vegetables, seafood pasta, calamari or Grilled fish.
In Ksamil you can also find Butrint national park with a city that is more than 2500 years old. The city itself is pretty fascinating, and the views from it help you understand why the Romans loved it so. It would take about 3 to 4 hours to slowly roam around so pack a lunch with you. There are buses to this park from Ksamil centre, or even from right outside your accommodation so just ask. If not, hitchhiking in Albania is common too.
Read up more about the city https://whc.unesco.org/en/list/570/