I do not know much about the extension but I would not recommend deploying this alongside MDE. This appears to be a solution for legacy OS versions. You really want one control plane for MDAV (preferably MDE). Even if nothing breaks you have configuration settings and exclusions to consider. I would expect MDE Tamper protection will likely break the extension as well.
https://learn.microsoft.com/en-us/azure/virtual-machines/extensions/iaas-antimalware-windows