You have quite a bit of full-time work experience, so it's good that you're focusing on European schools (which tend to skew older than U.S. programs).
Don't worry about having traditional, formalized managerial experience; it's more important that you can point to instances where you went beyond your job description and made a real impact on your company/team.
One other thought: You mention "stagnation" as a reason for wanting an MBA. That's a realistic reason why many applicant pursue an MBA, but you don't want that to come through too much in your application. Business schools want to accept people who are successful and whom can be made more successful by going through the program. People who are just "stuck" in a job aren't nearly as appealing to admissions officers.
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