Check-in and Delay Issues of Turkish Airlines on Flight TK7894

I had a terrible experience on my Antalya-Berlin flight TK7894! First, I couldn't complete the online check-in process as stated on the website and contract; the system kept giving an error. Despite calling customer service multiple times, I was told to try again later. I tried many times later, but it kept failing. Because of this, I had to take a taxi to the airport earlier than planned to check in at the counter instead of taking the tram. I waited unnecessarily for 50 minutes at the counter because, despite the short line, the process was extremely slow. Later, I found out that my flight was delayed by 35 minutes. This was quite inconvenient because I needed to catch a train after landing, but 35 minutes wouldn't have been too critical. Of course, the 35-minute delay turned into a much longer wait. The flight, which was supposed to take off at 16:10, only departed at 17:40! Despite all my efforts, I missed my train. Not only did I lose money, but I also lost valuable time. In one day, due to Turkish Airlines' mistakes, the money I spent on new tickets doubled the cost of my original flight ticket. I don't remember ever being this inconvenienced by any other company. I want to point out that, although their competitors are cheaper, I chose Turkish Airlines for a quality and comfortable journey. Will I choose them again? I won't even pass by their offices!