Yep. That is only for the amd version, but it is very worth it to get it and add an ax210 for $20.

Someone used a hammer to smash a window and steal stuff. Quick, ban hammers!!!

Getting rid of the tools to exploit vulnerabilities doesn’t get rid of the vulnerabilities, and security by obscurity is not security.

You can put graphene on a 4. It won’t be supported but will be more secure. Still not recommended by me or grapheneos. They say that the reason they support pixels is due to the security, not the aosp support, and that they will continue to develop grapheneos. Android 16 is the first new build with the changes and grapheneos is testing it now iirc. I would personally recommend seeing how 16 goes (possibly post after the update hits stable asking for user feedback) and decide based on that. You should probably get something new as the complete lack of security updates is quite bad but that could help you decide whether to go with graphene. Personally, I am on grapheneos and am not worried about it.