CEFR describes the action
A1–C2 is not a strict personality assessment or a list of mandatory rules. The scale describes what a person is able to understand and do in language in different situations.
For example, level relates to whether you can introduce yourself, explain an issue, support a discussion, or express nuance.
Why doesn't one level explain everything?
A person's reading, listening and speaking skills may differ. You can understand work emails well and still have difficulty speaking spontaneously.
Therefore, it is useful to track individual skills and real-world tasks, rather than hunting for a single number.
How to use a level for a plan
Choose the situation you need: call, presentation, interview or everyday conversation. Then practice vocabulary and constructions specifically within this task.
This way, the CEFR becomes a guide to the difficulty of the material, rather than a substitute for practice.