I would like to be able to specify whether a device is Active or Inactive. Furthermore, I would like this setting to be changed automatically based on the Last Seen date. If a managed device has not been seen in say 45 days, it should be changed to Inactive and not show up as a managed device on my monthly invoices to a client.

This is sort of a pain point for me. There are some devices that companies have as backups or are less frequently used. In this case, I can't bill them for a device that hasn't checked in even once during their billing period. Right now I have to manually adjust the managed device numbers on invoices generated in Atera to match what they actually have in production. This could all be solved simply by marking a device Inactive and excluding it from billing.