Really?
I had to look around a little to find an updated fork for AS, but I didn't look at the textures specifically. If they are indeed encrypted, I won't be of much help, sorry. Maybe you could work out something using Bepinex 6 preview for IL2CPP?
That's what I used!

Hello! I was wondering if you could share how you decrypted the files for Elnea Kingdom? I wanted to look into making a mod for it but using asset studio all of the texture2d files are encrypted.

Any help would be greatly appreciated, thank you for your time!

Alright, I have reached out to them as well, thank you. ^^

Hello Sleepy !
Thanks for reaching out.
I think you should rather talk with Drax. We had a few chats, but in the end, he/she is the one who managed to mod the game in the end !

Hi, similar question to Drax, would you be able to help with info about how to re-translate and otherwise mod Volcano Princess? :)

Sure did. Thanks man.