Olá pessoal! Talvez possa ser útil. Eu peguei esse erro na migração.
https://stackoverflow.com/questions/65058500/type-load-exception-in-ef-core-project
Method 'Fragment' in type 'Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper' from assembly 'Microsoft.EntityFrameworkCore.Design, Version=6.0.10.0, Culture=neutral, PublicKeyToken=adb9793829ddae60' does not have an implementation.
Como resolvi?
Precisa ser instalado: Microsoft.EntityFrameworkCore.Design
Funcionou perfeitamente.