Hello Ondrej,
I know only Runtime Version 5.1 & 7.2 are supported values by Get-AzAutomationModule at time of writing.
https://github[.]com/Azure/azure-powershell/issues/27235#issuecomment-2687160833
I raised a feature request for 7.4 and looks like that will be added by 15/05. It would be great if this could be added to your module after general release.
Thanks for your work on creating this function, it works great :).