To ensure any AEMaaCS customer can track the instance disk usage, I would like to have a monitoring in AEMaaCS Reports which tracks the disk usage similar to the feature in the AEM 6.x Cloud Manager functionality.

There is no disk usage monitoring available in AEMaaCS (in the CloudManager or elsewhere). Without Adobe Support input, a customer doesn't know this parameter. Alternatives via ACS AEM Commons reports are too time-consuming (XLSX work afterwards) or limited in scope (Asset reports only, no other content or full OS).

VW's Adobe Ultimate Support recommended I open a ticket here when they couldn't find a suitable functionality in AEMaaCS (E-001835519)

In AEM 6.x Cloud Manager, such a feature already exists: https://experienceleague.adobe.com/en/docs/experience-manager-cloud-manager/content/using/monitoring-environments - but there is no similar functionality for AEMaaCS.

Expected data (copied from AEM 6.x)

• Disk Space: The used disk space (in megabytes) for each mount point on the host. There are different metrics for each mount point. At a minimum, there are metrics for / and /mnt, but additional mount point metrics may be available depending on the specific instance configuration.
• Folder Size
• AEM Segment Store: The used disk space (in gigabytes) for the AEM Segment Store.