Turkish Airlines Connecting Flights Baggage Issue

I have two flights with Turkish Airlines (THY), one domestic and one international, with a 2-hour layover. When I couldn't arrange these flights as connecting flights during the check-in process via the internet and mobile app, I called customer service. However, the representative informed me that such an option does not exist, saying, 'You couldn't find it online because it doesn't exist.' This situation is unbelievable and disappointing. Unfortunately, THY's quality leaves a negative impression in this way. The fact that my two flights cannot be connected and that I have to pick up and recheck my baggage at Istanbul airport (according to the customer service representative) is frustrating. Despite having flights with the same airline within 2 hours, I have to handle my baggage myself. Unfortunately, we cannot find this information anywhere and have to learn it on our own. It's disappointing for such a large company. I hope the attitude of the customer service representative is misleading and that the baggage connection process is possible. However, I don't expect a response to this complaint.