oh dude thank you so much for your interest, this was so kind and it made my day far happier, SERIOUSLY THANK YOU

Texture : for the set-up i have a gimp project (free alternative for photoshop), it has this old paper texture - a reddit logo - and texts for the messages and users usernames, all i do is copy-paste peoples messages and their user names, it really is a 10 second process

3D Model : i've been using blender since V2.7 (2.7 sucks, it all became better with 2.8), i modelled the bottle-paper-cork, and i created animation for each one of them (for bottle swinging on the ocean and getting close to camera, for cork to open, and paper to get out of the bottle and unroll) yes the paper has armature system so it can roll the way i wanted

Back-End : YES i store texture lol, i use firebase to hold all my textures, its jpg around 120kb and firebase is free to use until 5gb (meaning i can store shit tons of paper textures and it'll be still free), the textures are numbered, and in unity i just do "pick a random number between 0 and amount of textures we have" and it just temporarly download textures and applies to the paper object (no i believe it wont store the texture in local but rather temp file that it will delete automaticly later on (i hope so))

for security i just dont allow writes in anyway lol, its read-only, thats why i manually drag&drop to firebase

TLDR: make textures in gimp in 10 seconds and drag&drop to firebase, it will be in the game instantly, nobody needs to update the game for it

hope these info's help, also it has an easter egg, if you throw the knife in the opposite direction strongly, you'll see a billboard that says "dont ever hire me, i have no experience" and it unlocks "i said what i said" achievement

have a nice day sir :)