You know that assessment values are not stored in the database, right? Which is why we always recommend to use equations.
I first set up equations for all questions. It didn't do what I wanted.
Then you did it wrong.
Jokes aside, you can do everthing you can do with assessments also with equations (and much, much more). You can even use the assessment values within your equations.
Once you have the final value of the score that you created (it doesn't matter if it is via assements or equations), you can save that value in an equation type question. Based on that value you can write a text into an equation type question and display it there.
You can then include this text in your end message or your confirmation email, just like any other value of other questions, via {questioncode}