I want to use the new Prompt Studio but my Preview Release is still not available

First point, make sure you requested it via the release preview opt-in, which I'm assuming you did already. They say in the help it will take approximately 3-5 business days to create the RP account after you submit your request. Although it did feel like mine took a particularly long time this go around. I'd probably drop a support ticket if it's been a while since you requested it.

Yeah, I did it. Still waiting 😕

yeah mine was really slow last time (took like two weeks) and it's been similarly slow this time