Hi @i.klek , welcome to Microsoft Q&A community.
To answer your query, unfortunately there is no direct or automated way of achieving the migration or converting the Azure Mysql database into Azure Sql database.
However, using 'Sql Server Migration Assistant for MySQL' tool it becomes very straight forward as it gives you both source and target database where in we can choose Azure Mysql and Azure Sql database respectively. Please refer to the link for more details. Below is the screenshot of the same tool.
Another way is to achieve this is using Azure Data Factory. You can refer to below link for more details:
You might have already looked into these but please let us know if you need any help with these and we can continue our discussion.