While trying to restore the recent release of .NET MAUI Community Toolkit v6.0.0 and Markup Toolkit v3.3.0, faced this issue This package is signed but not by a trusted signer.
A similar signing issue came up while installing the workload of .NET MAUI on .NET 8 RC1. However a workaround was provided to overcome the signing issue by bypassing the sign check by trusting NuGet as the package source.
Developer Thoughts 