In lieu of ES File Explorer, what about this one from F-Droid…
Secure File Manager Beta (File manager for keeping your files in safe) - https://f-droid.org/packages/com.securefilemanager.app
It implies that it’s best on an unrooted device.
There’s also this one…
DroidFS (Store & access your files securely) - https://f-droid.org/packages/sushi.hardcore.droidfs
Supposedly Amaze file manager can also do encryption. Amaze is more up to date using the IzzyOnDroid repo.
Amaze - IzzyOnDroid F-Droid Repository - Amaze - IzzyOnDroid F-Droid Repository
@Confused , you didn’t say which tools you’ve tried before so excuse if some of these were already tried.
I don’t do encryption so I don’t have any comments on them.