how to use table name instead of entity model with dbcontext?

I need to get entity model object by passing string name of table to use that object later on as dataset where i can apply LINQ to extract data.

for example

function List<string> test(string tablename)
{
  var TEntity = _dbContext.someHowGetEntityObjBytablename(tablename);
  
  return TEntity.select(s => s);
}