I am buying a new iphone 14 plus. Unlocked to bring to Turkey to be used there via Turkcell carrier. I want to make sure they have been supporting eSIM activation since the iphone 14 s dont have a physical SIM card slot anymore. Thank you.

You'll need to do some homework on the Internet, or get in touch with the carrier directly.

However, this blog suggests that Turkcell does support eSIM.

This page (in Turkish) from Turkcell also comments that they support eSIM.

A translation of that page provided the following text:

eSIM is an embedded digital SIM technology in compatible mobile phones instead of a physical SIM.

• Individual: You can come to our stores with your mobile phone using eSIM technology, convert your SIM card to Turkcell eSIM digitally and start receiving service from our network.

*If you are buying your iPhone 14 outside the US (and you didn't mention where you are) it will have a tray for a physical SIM.

International iPhone 14s will ship with SIM card clots.