There are two important factors here:
- Your goal/interests
- How you practice
If you are motivated by the idea of developing a very good technique, you will need to be more technical in your practice. You must be aware this is an investment that does not pay off right away. You have decided to learn more slowly in order to gain a better general skillset that applies broadly to many types of music. Scales are the simplest technical exercise, and there are lots of others.
If you are motivated by actually playing music, you may do a little technical exercise to start your sessions, but you'll generally be trying to learn a specific piece, and you'll be focusing there.
How You Practice
This is the overlooked aspect so often left out. Even after you know your goals, you must practice well to actually ensure progress with any goal.
What does that mean?
- Deliberate (you must have some objective with a phrase or portion of the music, e.g. play it smoothly, play it uninterrupted, practice a particular fingering, etc.)
- Consistent (you must repeat the practice in the same way each time, e.g. play a phrase with the same fingering so you are reinforcing something consistent and not giving random info to your brain)
- Correctness, at some speed (after having a goal, you must ensure you can achieve correctness of your objective, no matter how slow you must play to make it possible).
- Played with the right fingering, or at least a workable fingering
- Played at a continuous rate without pauses
- Played where each note has the right relative duration (even if tempo is slow)
- Played with reasonable dynamics (reasonably consistent volume)
- If more advanced, played with a good phrasing
- Play a section correctly with the left hand
- Play a section correctly with the right hand
- Play a section correctly with both hands
- Practice a specific fingering for a small section (ensure the fingering is possible to transition to from the previous section, and leaves you ready to play the next)
The good news is, if you practice anything well, you will make progress with it. The better news is that you don't have to be an expert to make this work for you. Find something you can feel reasonably confident to try that fits your knowledge, but do it well.
While you don't have to practice this way the whole time at the piano, if you want to see noticeable results, you will need to do this some of the time.