Get all private filters

Hi all
I hope you can help.
I am using to get all Filters on our instance. Now, I know it says that it only returns filters owned or shared with the user I make the API call with but how can I get all as an admin / API user?
ie. we have under 4000 filters but the “…filter/search” endpoint only returns the total of just over 1600 filters.
I want to get all so I can bulk add permission so that we can review for a clean up
Please advise?
Thank you

I hope this gets a bit of visibilty and someone has a workaround or fix for this please? Thank you

Someone? Anyone?