The app will send a response in the sense that there is a popup that says ‘Sent’.
What I would do in your case is create a template column on the sheet you gave the form button. Fill it with a value like ‘Completed’. Do the same thing on your form response sheet. Next create a relation column that links both template columns. Finally create a lookup column that uses the relation to get an array of emails that have completed the form. You can use this lookup column to set visibility by signed in user to hide the form button and show a different link to screen button, or you can use the same relation for an inline list filtered by signed in user.
On your main page, use the list in a card or tile style to show a template column from the form responses that’s built to say congratulations and show the test results on the tile or card. You can build that template by creating all the math and if then columns you need in the form response sheet to build a template that says congratulations with their results.