The recently lost file upload feature in the Nextcloud app for Android

Disclaimer: I don't use nextcloud, and have not looked at their app specifically, this is just a surface level observation from my relatively informed perspective.

My take: SAF would work for this use case, as others have already mentioned.

Google Drive does not have the permissions that next cloud claims Google is giving preferential treatment to, and is delivered via the Play store in the same way nextcloud's app is.

As others have also observed, permissions such as MANAGE_EXTERNAL_STORAGE have been rampantly abused in the past, often in horrific ways.

Let me guess, loan shark apps, or is there something even worse that I wasn't aware of?

(Essentially ransomware that people "voluntarily" install in order to get a predatory loan, often without knowing how it actually operates. If they fail to pay, not only is their phone locked, but the data from it is used to threaten/extort them, from threatening to send their nudes to their contacts to death threats to relatives identified from the data - https://www.welivesecurity.com/en/eset-research/beware-preda...)