I think you're building up a skill in addition to these languages - the skill it takes to fearlessly pick up a new language! It can feel like you're not mastering any one particular thing, but I find that's hard to do until you have a real reason to solve a specific problem with a specific language. If you've got basic programming knowledge in a variety of languages, you've probably got a good grasp of the abstract concepts - possibly better than if you'd stayed with just one.
Still, it's a good idea to keep an eye out for situations where you can deepen your knowledge and mastery in an area you're interested in. Try solving new problems, or implementing design patterns, rather than solving the same problems in a new language.
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I think you're building up a skill in addition to these languages - the skill it takes to fearlessly pick up a new language! It can feel like you're not mastering any one particular thing, but I find that's hard to do until you have a real reason to solve a specific problem with a specific language. If you've got basic programming knowledge in a variety of languages, you've probably got a good grasp of the abstract concepts - possibly better than if you'd stayed with just one.
Still, it's a good idea to keep an eye out for situations where you can deepen your knowledge and mastery in an area you're interested in. Try solving new problems, or implementing design patterns, rather than solving the same problems in a new language.