Turkish Airlines Did Not Allow Elite Plus Upgrade

Hello, I have been a THY customer and an Elite Plus member for 8 years. I have observed that THY has implemented a policy that restricts the use of free upgrade rights, which was not noticeable at first but has been ongoing for a long time. I frequently fly the Boston-Ankara route and after exhausting my THY miles, I decided to fly with Lufthansa, which is also a Star Alliance member. For this route, I have the option of flying Premium Economy on the Boston-Frankfurt leg at a competitive price compared to THY's mid-tier economy fare. To fly to Ankara, one needs to transfer in Frankfurt instead of Istanbul. If you need to purchase a higher-class economy ticket, you might consider Lufthansa's Business Class option. Despite THY offering flights to every point in the USA, it is incomprehensible that there is no direct flight option from its capital. When you try to upgrade your economy ticket using your free voucher rights, the system locks up, preventing you from completing the process. This issue persists even if you purchase the ticket 5 months in advance. Trying to use connections might be an option. Suppose this opens up 24 hours before the flight, you need to call to complete the process, as there is no menu available in the app. However, having an experienced representative is crucial because I have observed that employees are generally not sufficiently knowledgeable on this matter despite the exclusive customer service for Elite Plus members. In USA-Turkey flights, THY used to implement low prices to outcompete American rivals, which also affected air cargo prices. I am considering discussing this situation with our former state governor, who is now the US Secretary of Commerce. Currently, ticket prices are quite high for flights in the same category. If you are flying directly to Istanbul from America, flying with THY is advantageous. However, if you are flying to a place like Ankara, a transfer is necessary. Unfortunately, THY management does not see Ankara as a capital city, which limits international flight options from this point. A route through Germany, such as Boston-Frankfurt-Ankara, can be recommended. I urgently request THY management to consider the feedback of their customers living in America and allow us to use the rights they offer. Even if you give me 10 rights, it means nothing if I am not allowed to use them.