Error after Error. Please Help

Just starting out with Unity. Had a lot of issues getting any tutorials added so I reinstalled. Now packages importing and everything is in the scene Panel. But when I hit play, I get "All compiler errors have to be fixed before you can enter playmode!"
There are only 5, but they are repeated (not in order) over and over many many times.
Here is a list from first to last.

Library\PackageCache\com.unity.package-manager-ui@2.0.3\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?)

Library\PackageCache\com.unity.package-manager-ui@2.0.3\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?)

Library\PackageCache\com.unity.package-manager-ui@2.0.3\Editor\Sources\UI\Common\LoadingSpinner.cs(19,42): error CS0308: The non-generic type 'LoadingSpinner.UxmlFactory' cannot be used with type arguments

Library\PackageCache\com.unity.package-manager-ui@2.0.3\Editor\Sources\UI\Common\LoadingSpinner.cs(27,34): error CS0115: 'LoadingSpinner.UxmlTraits.Init(VisualElement, IUxmlAttributes, CreationContext)': no suitable method found to override

Recursive Serialization is not supported. You can't dereference a PPtr while loading. (Constructors of C# classes may not load objects either. See stacktrace.)
0x00007FF6A16C603C (Unity) StackWalker::GetCurrentCallstack

 

Says there is some issue with either some package or the package manager itself in this project. Is this a new empty project? If not, are you getting this same issue with a new empty project?

A project's library folder can safely be deleted with Unity closed. Unity will regenerate it the next time you open the project, which is sometimes needed if there is an issue with the files in the library folder.

 

It comes down to your target demographics, it seems. If you want a large market using a wide range of devices, then it's Unity. If you want a smaller market composed of people with the latest machines, then it's Unreal.

I am new, too. I had a terrible time even installing Unity. The Hub wasn't working at all. I got a ton of errors trying out the tutorials. That was a matter of weeks ago. I'm having a much better time now.

I'm glad I stuck with it, now that things are working. Unity should be the right tool. If worst comes to worst and I eventually run off to Unreal, I figure I'll have learned enough here that learning Unreal will be much easier. My time here won't be completely wasted.