https://wccftech.com/download-ios-15-beta-3-without-developer-account-right-now/

You can download and install iOS 15 and iPadOS 15 beta 3 without a developer account with Apple right now in a few easy steps.

Apple has released beta 3 of iOS 15 and iPadOS 15 to developers and it can be downloaded over the air right now. Those enrolled in the Beta Software Program will receive the update after a short while.