Hi @HekatheGreat, your post in another thread, No answer to three of my e-mails/Unhappy with Samsung s9+ - #12 by HekatheGreat reminded me that I had not followed up here. You have been correct to say that when a phone is encrypted TWRP cannot deal with it.
As an aside, when a device is encrypted as shown in Settings > Encryption and you enter TWRP, you have very limited powers. As far as I understand it, if you take a step where you are asked for the password, when the phone is encrypted and you know that you set no password, you press Cancel in order to pass the default_password. Now you see the limited powers of TWRP in an encrypted phone. Please contradict me if I am wrong.
I wonder if you asked helpdesk@e.email for advice to undo encryption?
I found this link which covers ways that you might try undo encryption. https://yoodley.com/solved-twrp-asking-password-to-decrypt-data/ – I realise that the reason you might want TWRP right now is to make a data backup, before wiping the device, but (I guess) this will not be possible.
The method #3 is what I would try, using “no-verity-opt-encrypt.zip”. This can be found from the device install page Install /e/ on a Samsung Galaxy S9 - “starlte” and copied here.
Patch the device
- Download the patch from here
The page is unhelpful in not telling us what the patch does !
An altenative method of patching the device from a PC is given there.
Of course, you still need to be advised to “backup your data first” !
However if you have learned to love an encrypted phone, I would fully expect regular OTA updates to be ok.