If you haven’t already been there I would recommend Istanbul. There are regular and relatively inexpensive flights from Antalya. I would allow for at least 3 nights in Istanbul (or more) because there is so much to see and do there.
North Cyprus is another possibility - again there are regular flights from Antalya to Ercan. You would need to hire a car (they drive on the left like us) that you could pick up and drop off at the airport. Again, 2/3 nights minimum to see the sights, including Salamis.
I would agree that cappadocia is wonderful (I have been there twice) but the bus journey is quite long - I think it is around 12 hours from Antalya to Nevsehir via Sparta and Konya.
I am sorry to say that I find Antalya and the coast to the east and west overdeveloped and unappealing. It is full of mega hotels. I visited this beach in 1993 when it was pristine - quiet and family oriented with a lokanta serving wonderful Turkish food. This is what it is like now:
https://lara-beach.com/
Not for me at all, I’m afraid, but you can find culture and places of interest elsewhere.