https://wccftech.com/download-ios-13-beta-4-ipados-beta-4-without-apple-developer-account/

Here’s how you can download iOS 13 beta 4 or iPadOS beta 4 without an Apple developer account on your iPhone, iPad or iPod touch.

Just a while back, Apple released the fourth beta of iOS 13 and iPadOS. If you are eager to try it out right away then you have two methods to get onboard. You can either sign up to the public beta which is absolutely free. Or, you can download the developer iOS profile straight onto your device and get in on the action. The latter is a paid method, but the obvious advantage is that you get access to beta releases sooner compared to public beta.