can't install ARKit XR Plugin newer than 2.2.0 preview.1 in Package Manager

I've beeng getting super funky behaviour with the package manager and the latest preview versions of the various AR related packages, but in my case primarily the ARKit XR Plugin.

Basically I want to use 2.2.0 preview 6 as documented here https://docs.unity3d.com/Packages/com.unity.xr.arkit@2.2/manual/index.html

specifically I need to use Apple's AR Coaching overlay.

But I can't see the latest package previews that I know are available (for example if make a vanilla project I can see all the latest package previews up to 3.0.0)

I also tried deleting the entire library and package manifest for the project, and in that case I was able to see all the preview packages again and was able to install ARKit XR 2.2.0 preview 6, but then after restarting the Unity project I now cannot see the latest packages!

I am in Unity 2019.2.11f1 and using the latest Xcode and iPhone blah blah blah it's definitely not related to those versions as I tried this in older versions of Unity as well as the latest beta version, which fixed it but introduced other problems.

 

btw also already tried updating all related plugins / dependencies, didn't help, I also can't see there latest preview packages

also I already have "show preview packages" and "show all packages" turned on

 

anyone?