Hello, @Dominik Mańkowski !
How to check in which zones in a region VM size is available?
Using the az command you listed is the correct approach for determining if a SKU is available in a region. The issue you are running into here is that the HBv4-series was just released in June of 2023 and when we check the Azure products by region page, we see that it is not yet available in West Europe:
You would need to deploy either in East US for the time being or use an HBv3-series VM in West Europe.
I hope this saves a bit of time in searching and thank you for your interest in the HBv4-series. Hopefully it will be available locally in the near future.
Your feedback is important so please take a moment to accept answers.
If you still have questions, please let us know what is needed in the comments so the question can be answered. Thank you for helping to improve Microsoft Q&A!