In iOS 15 and 16, once an app gave permission to access Contacts, Widgets (and Lock Screen Widgets in iOS 16) could access Contacts. 16.1 beta 1 and 2 apparently no longer allow this (and there appears to be no work around, as Widgets can't ask you for permission separately from the parent app). My app (Curmmunicate) in the App Store will fail if this doesn't get a fix as it relies on this feature.
Have filed a report: FB11563817 (Contacts not accessible from Widgets in iOS 16.1 betas). Report includes an Xcode sample project showing the issue.
This seems to be fixed in iOS 16.1 beta 4. Crisis averted!
@freyherme, I was just about to message you and ask if you had a fix for Calendar in the beta. Seems you do, so great news!
My bug report is still open, and never received any updates from Apple. That's frustrating. But at least they fixed it.