Compilation errors with Unity 2021.3.11f1LTS and Driving Simulation begniner's project

1. Script updater for Library/Bee/artifacts/2400b0aE.dag/Unity.PackageManagerUI.Editor.dll failed to produce updates.txt file
2. Library/PackageCache/com.unity.package-manager-ui@2.0.7/Editor/AssemblyInfo.cs(7,12): error CS0246: The type or namespace name 'UxmlNamespacePrefixAttribute' could not be found (are you missing a using directive or an assembly reference?)
3. Library/PackageCache/com.unity.package-manager-ui@2.0.7/Editor/AssemblyInfo.cs(7,12): error CS0246: The type or namespace name 'UxmlNamespacePrefix' could not be found (are you missing a using directive or an assembly reference?)
4. Library/PackageCache/com.unity.package-manager-ui@2.0.7/Editor/Sources/Services/Common/Resources.cs(1,32): error CS0234: The type or namespace name 'UIElements' does not exist in the namespace 'UnityEngine.Experimental' (are you missing an assembly reference?)
5. Library/PackageCache/com.unity.package-manager-ui@2.0.7/Editor/Sources/UI/Common/Alert.cs(2,32): error CS0234: The type or namespace name 'UIElements' does not exist in the namespace 'UnityEngine.Experimental' (are you missing an assembly reference?)
6. Library/PackageCache/com.unity.package-manager-ui@2.0.7/Editor/Sources/UI/Common/LoadingSpinner.cs(2,32): error CS0234: The type or namespace name 'UIElements' does not exist in the namespace 'UnityEngine.Experimental' (are you missing an assembly reference?)

These compilation errors show upon opening the project in Unity editor. I couldn't find much on Google and forums. What am I missing? Thanks.

Unity: 2021.3.11f1LTS
Development OS: Ubuntu 22.04 LTS