don't worry guys. google has posted a blog post
https://android-developers.googleblog.com/2025/09/lets-talk-security-answering-your-top.html
and has cleared the issue at the very start.
1.Does this mean sideloading is going away on Android? Absolutely not. Sideloading is fundamental to Android and it is not going away. Our new developer identity requirements are designed to protect users and developers from bad actors, not to limit choice. We want to make sure that if you download an app, it’s truly from the developer it claims to be published from, regardless of where you get the app. Verified developers will have the same freedom to distribute their apps directly to users through sideloading or through any app store they prefer.
so you can sideload freely, with the tiny tiny condition that you sideload just the apps that google approves of.