Safely Delete Term Sets

We currently have a number of Term Sets within our Term Store.  To the best of our knowledge these were created as tests and are not in live use.

I have run the following PowerShell query and get no results for any of our Term Set guids:

Submit-PnPSearchQuery -Query "{Term Set GUID}" -CollapseSpecification "SPSiteUrl:1" -RelevantResults -SelectProperties "SPSiteUrl" | select SPSiteUrl

1. Is the above query enough to ensure the Term Sets are not being used, is there another method to report used Term Sets?
2. Knowing that deleted Term Sets are not recoverable is there a best practise for deleting these to ensure we won't irrecoverably break peoples lists?

Any advice or guidance on cleaning out the mess of test data is appreciated.