The Safari beta was available for a little bit for Big Sur, but the images didn’t open up. They has since removed it as a download.

mandarismoore.com

@mandaris oh! I wonder what is horribly broken? I am using it now, hope it doesn't explode on me!

@mandaris I saw too! Weirdly, it's the same version I had previously? 🤷‍♂️ Not sure what was going on there..