At some point, despite the consistency of practice, it seems that not much improvement is happening. You can still formulate sentences but they aren’t as elaborate as you wish, and your speech isn’t very diversified. That’s not something bad. It just means that you need to adjust your practice. It’s time to stop caring about the amount of time and start caring about what you actually do during that time and how you challenge yourself.
The first thing you can do is increase a little bit the level of difficulty of what you try to say but still keep the sentence structure more or less the same. If you normally talk about actions you do, for instance, try to include your purpose or opinion as well. So instead of just saying, “I watched a movie,” say, “I watched a movie because I needed to relax.” That will make you think a bit and connect ideas in your head, which is always good for fluency and flexibility. Remember to just push yourself a bit and not get lost.
Another problem people face during the plateau is practicing the sentences they know without changing a thing. That’s good and necessary in the beginning, but at some point you need to move forward. So try changing the sentences you normally use. Turn them into questions or change them from simple present to simple past, for instance. If you always practice, “I like this place,” try “Why do I like this place?” or “I liked this place yesterday.” That will make you create new patterns without necessarily using entirely different sentences.
Try to have a daily practice where you first repeat the sentences you know for some minutes; then change some of them and afterwards try to talk about something a bit more difficult. You could explain why you made a certain decision, for example, or talk about what you did the day before and explain it a bit more. Don’t worry about perfection but rather try to communicate and express your ideas.
As you start practicing like that and introducing some variation and challenge, you’ll slowly start to overcome the plateau. You won’t see much difference at first, but every little step you take will add something to your ability to express yourself. Little by little you’ll see your fluency improving and your capacity to connect ideas will also increase.