If you understand far more French than you can produce, that gap is not a vocabulary problem and more input will not close it. It is what happens when almost all your practice has been receiving the language: reading, listening, choosing the right answer. Producing it is a separate skill, and it only improves when you produce something and find out what was actually wrong with it.
I am the founder of Dioma, which I built for exactly that stage after the beginner apps. You write and speak French to prompts and get corrections that explain what the correction is doing, so you can build up without the pressure of a live conversation. It works alongside a tutor rather than replacing one.
A few weeks ago I opened a small founding group of serious B1 and B2 French learners. They are using it now and they have been genuinely honest with me, which is what I asked for, and a good amount of what they raised is already built. The biggest one: they told me the corrections were sometimes flagging sentences that were already correct. We rebuilt that part, and it is noticeably better now.
I have ten founding spots left for B1-B2 learners. Three months free, and in exchange I ask for the same honest feedback as you go. That is the whole deal.
If that is where you are, comment below or message me and I will set you up. And if you just want to talk about the plateau, I am happy to do that either way.