Suspended and archived users, as well as those without an active Gmail inbox, are by default treated in SignatureSatori as standard users. However, in some cases not having them around in the User list can be beneficial.
If you want to remove these users from SignatureSatori (and prevent them from being synced there in the future), you can do so very easily in Settings - scroll down to "Handling Users Ineligible for Signatures".
If you have suspended users in Google Workspace, but they still appear in SignatureSatori, it's because the changes haven't been synchronized. You can do that manually or set it up to happen regularly.
Please keep in mind that it is common for service accounts not to have an active Gmail inbox. If you want to use these accounts as admins in SignatureSatori, the "Exclude users without mailbox" should be left unchecked.