For many years I had a good level of my English, but not enough to feel myself 100% comfortable on my work calls. I tried many apps but they were useless, cause they focus mostly new learners. However, Fluently finally helped me to progress. Its feedback on your speech is so useful. It really helped me to fix my grammar and pronunciation mistakes. Also the app have a decent AI tutor and I started regularly practice my speaking skills with it. So, if you stuck in English for a pretty long time, Fluently might be a good option to move forward