Grant MANAGE_EXTERNAL_STORAGE And REQUEST_INSTALL_PACKAGES on Android 11+ using DPM and/or Root access

Question

I would like to know, how to grant the permission to access ALL FILES with MANAGE_EXTERNAL_STORAGE.

(I managed to get it to give me MEDIA ONLY access, using DPM and setting the package permission to GRANTED)

I would also like to know how to set the current package to be able to install "unknown sources apps". (But without this I can live)

I want to be able to do it completely programmatically. Device owner privileges and/or root is acceptable.

I know how to set it with intents, I do not want user input of any sort.

Thank you in advance.