You need to go to
Samsung Members App
Check the front page where the advertising banners are. If you see the banner, you can see if you can enrol. If you don't, sadly you're not using an eligible device.
Please remember beta is test software and you should only enter the beta programme if your prepared for the risk and willing to provide feedback on bugs and issues etc
I am not employed by Samsung nor do I receive any remuneration as a Samsung Members Star.
My device is an S25 Ultra.