Solutions

Try uninstalling updates of the Files app following the instructions here
Use Shizuku with ZArchiver (closed-source): ZArchiver Settings > Root > Root type > Shizuku
Connect your device to a PC with USB, enable file management and manage files
Use ADB and manage files using its commands
For Polyfield or LAC, check this

Uninstalling Files app updates

Uninstalling updates of the Files app might let other apps request explicit access to Android/data again.
To uninstall these updates:

Device Settings > Apps > All apps/Manage apps > Files (the one with the blue icon, name depends on your language) > Uninstall updates

. This app will most likely be hidden from the list by default, in this case look for an option to un-hide system apps. Note that these steps may vary depending on your device.
If you are unable to do this, use other solutions listed here.

LAC & Polyfield workarounds

LAC:
- Use LAC Tool, it has Shizuku support
- Copy .txt link of the map you want to download and paste it on map name field, then hit create
- Copy link of the wallpaper you want to import and paste it on in-game cellphone settings
- Manually manage files, check these first
  - Android/data/com.MA.LAC/files/editor contains your maps
  - Android/data/com.MA.LAC.files/wallpaper contains in-game cellphone wallpapers
  - Android/data/com.MA.LAC.files/screenshots contains screensots taken using in-game cellphone
Polyfield:
- Use PF Tool, it has Shizuku support
- Download maps from in-game maps list
- Manually manage files, check these first
  - Android/data/com.MA.Polyfield/files/editor contains your maps