You can use the REST API, make sure to do a Connect-CisServer first.
$sys = Get-CisService -Name 'com.vmware.appliance.system.version'
$rec = Get-CisService -Name 'com.vmware.appliance.recovery.backup.job'
[PSCustomObject]@{
'Last updated' = $sys.get().install_time
'Last file-based backup' = $rec.get(($rec.list() | Select -First 1)).end_time
}