Not able to build and run my project

I am trying to build and run my first-person experience but receive these errors each time. I am using Unity 2021.3 version, all my packages are updated and I reloaded my assets as well. The first error showed

, I do not have that file and don’t know how to install it. I deleted the libraries folder and reopened Unity as well.
Any help would be appreciated as my deadline is soon!

First get a backup of your project just in case!

  1. Close Unity
  2. Delete Library and Temp folders
  3. Open Unity

Once I close Unity, the temp file disappears and I did already try deleting the library folder and opening it again. No luck :frowning: