@Jakub Sykora
Sorry to hear that you are having slow speeds when downloading blobs. Hopefully this was just a temporary issue and is functioning fine for you now. If not I recommend checking this existing Q&A thread for some suggestions and let me know the results. Azure publishes 60 MB/s scalability target for a single blob. If the network and client machine can handle the traffic, then we will send it. For more information see here.
Hope this helps! Let us know if you have further questions or issues.
-------------
Please don’t forget to "Accept the answer" and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.