As others have said, meditation isn't just about a still mind, because a still mind is being found in order to be a step towards something. It''s not an end in itself (or at most it's only part of the desired end, not the whole of it).
So congratulations,you have found stillness easy, and you're doing well, but don't mistakenly imagine that this means you've "accomplished" meditation, in its deeper sense. Now to use that state.
There are two aspects to this - look carefully at what you already do, then put it in context to understand what next.
As a first question, I have to ask you to consider how sure you are, that you have accomplished what you believe you have done. I "get" the monofocus point, but having a still mind, seemingly empty and without thoughts, doesn't necessarily mean an inward watching mind,and doesn't necessarily mean you're seeing what's there. Be careful in assuming it is.
Perhaps you are taking "no thoughts" too literally. In meditation, you are watching for/remaining aware of everything. That's one reason stillness matters - the ability to notice what passes within, and move beyond mind, is immediately limited by "noise to signal" - the chatter, distraction and instability of the observing one.
In this context, one wants to stay alert, and watch and become aware of (but not reactive to) anything that arises.
A rich and important source of things, is ones immediate reactions and "involuntary" behaviours. Your eyes blink, the heart pulses, you catch the edge of a thought "how long have I been sitting" in the moment it arises, there is a sound outside and for a brief moment you feel yourself move as you react to it and decide what it means. And "yes you do" - if you didn't, you wouldn't react to a fire alarm or scream of a loved one, any more than a car driving or foot on the stairs, because you wouldn't perceive the sound or the difference between them. Literally, anything that causes the edge of a thought, or internal change of any kind, one is seeking a state of awareness of it.
A good one here is a body sensation like an itch, or ache. Do you ever scratch, ache, or move when sitting? I do. Notice that these are just sensations, the thought to scratch or move arises separately. You can see these arise separately. As these are common and observable, these are really good ways to check what you are doing when sitting. For example, when sitting, I notice that what I think of as an itch, is actually an irritating burning sensation, that arises, ripples a bit, intensifies, an instinct to move a hand arises, a thought to do so occurs to make that happen, and if I watch it a while, the itch gradually moves, then vanishes. And I can watch all those play out, and stay detached from it. Even if I do scratch, I just let my body and mind do what they will, and observe, like any other observation. This might help.
But then there is the question, "why"? What does this achieve, why meditate anyway? The aim of meditation is not just to sit untouched and have a still mind. It is more about becoming aware of how thoughts (in all ways) arise in your own mind, and developing detachment and awareness of them in daily life.
There is a saying, I forget by whom, to the effect that in the tiny fraction of a second between the raw sensation, and the reaction - that is where free will and freedom reside. In a way, that is a good description of meditation's real goal. So a still mind isn't the final aim, it's a prerequisite needed to make observation, and then more refined observation, of those split seconds, possible and more automatic. It's also to prolong the space between the two (and allow freedom and detachment into that space where judgement and reaction usually occur).
So, now you have a still and aware mind when sitting. But when you stop sitting, what then? The aim is to keep within this state in everyday life. The concept of "walking meditation", where you walk, or move, while staying within that state, sounds like a place you could go next.