Braguzz:You can derive that from diagnostics using the path I recommended. If you would like to use out of the box solutions we have partners that provide their solutions in the Azure Marketplace. See here the partners we are working with: https://docs.microsoft.com/en-us/azure/virtual-desktop/partners
MicrosoftBraguzz: Can you give more context on what exactly you are looking for? You can derive approximate usage using diagnostics data. We recommend to push data to your Log Analytics workspace using New/Set-RDSTenant cmdlet (link: https://docs.microsoft.com/en-us/powershell/module/windowsvirtualdesktop/new-rdstenant).
On using Log Analytics you will find documentation here: https://docs.microsoft.com/en-us/azure/azure-monitor/log-query/get-started-portal
