Yes. You can not download apps that are not released for turkey.
Some apps might be missing in TR store. The ones you already have will continue getting updates. You can make additional Apple ID set to your region which you can use to download apps that are unavailable in TR.
Have you ever encountered problems with the subscriptions? I have one app that is constantly switching between pro and unpaid, constantly locking out features(mind you, I was using the app just fine before that).
PS. VPN turned off.
I have never had any problems. I pay for YoTube, Disney+ and Apple Music and rent movies through Apple TR.