Question Using render Texture of Object with Transparent background

Hello there,

first and foremost i apologise if this is the wrong subforum to ask in but this is my first time Posting and i got kinda lost.

Im using unity 2021.3.4f1. and HDRP

So what i want to do is have a a preview of a selected character in the main menue of my game. I followed

to get what i want and it works fine so far except that i want to have transparent background on my render Texture but the option he shows in the video no longer exists and the best i can do is use a black colored background.https://imgur.com/a/5X8Gogy this is how it looks when i try to use "none as background". I've searched around in the webs for quite some time trying different things but some optoin is always missing in the unity version i'm using any help or pointers would be much appreciated