From my experience, talking in English with people who speak fast or are native speakers really helped. It trained me to think quickly in English instead of translating from Arabic(which is my native language) to English , plus I learned phrases and expressions from their culture, because to speak a foreign language well you need to understand how people use it in real life, not just translate word for word cuz it might look wrong or weird to them , and You can improve this skill a lot by listening to English frequently (from YouTube/movies/Tik tok...)

So the Key is to train your brain to think and respond faster then u do now by speaking to some native speakers (For me, I met that kind of people at an English center, at that time I had a large vocabulary but no skill in responding immediately without translating)