You watch a film and follow most of it. Then someone asks you a question and nothing comes out. That gap is not a failure of memory. It is the normal distance between the words you recognise and the words you can produce.
Recognition is a much easier task
Understanding a word means matching it against a form someone else has already supplied. Producing it means retrieving the form from nothing, with the right ending, in the right order, while the conversation keeps moving. Most learners recognise several times more words than they can use. That ratio is normal in your first language too — you rarely say half the words you read without trouble.
What moves a word across the line
Retrieval, not review. Reading a word again strengthens recognition. Saying it from memory, in a sentence you built, is what makes it available later. The cheapest version of this: after you meet a new word, immediately use it in three sentences about your own life. Not example sentences — yours. Specificity is what makes it stick.
Accept a smaller working set
You do not need to activate everything. A few hundred well-drilled words used confidently will carry more conversation than three thousand you half-recognise. Pick the words you would actually need this week. Leave the rest in recognition, where they are still doing useful work every time you listen or read.
The gap never closes completely, and it does not need to. It only needs to be narrow enough that the words you want arrive while you still want them.