Google specifically allows the use of the permission[1] if the app falls in a set that truly require it to function.
File managers
Backup and restore apps
Anti-virus apps
Document management apps
On-device file search
Disk and file encryption
Device-to-device data migration
This Nextcloud app seems to be an app that mirrors your Nextcloud storage to your device, and I cannot understand why it would need all access to any other data stored on the external device -- with the enormous risk that entails -- much less that can't be selectively picked by the user. It isn't a file manager, it isn't a backup utility, it's a cloud provider with local mirroring. I get why Google told them to do things otherwise.
Another comment mentions this is "bad faith" security and that's just overly cynical. Android and iOS both suffered from basically trusting app developers, and both were burned for it. Hardening down and making apps only request precisely what they actually need seems to be a massive user positive.
File managers Backup and restore apps Anti-virus apps Document management apps On-device file search Disk and file encryption Device-to-device data migration
This Nextcloud app seems to be an app that mirrors your Nextcloud storage to your device, and I cannot understand why it would need all access to any other data stored on the external device -- with the enormous risk that entails -- much less that can't be selectively picked by the user. It isn't a file manager, it isn't a backup utility, it's a cloud provider with local mirroring. I get why Google told them to do things otherwise.
Another comment mentions this is "bad faith" security and that's just overly cynical. Android and iOS both suffered from basically trusting app developers, and both were burned for it. Hardening down and making apps only request precisely what they actually need seems to be a massive user positive.
[1] - https://developer.android.com/training/data-storage/manage-a... - the exclusions can be found at the bottom.