Hi @dsFra
This is possible but not straight forward.
I see where you are going with "if(equals(...,"Outstanding),5,if(equals(...,"Beyond Expectation"),4, ... etc ... ))" and what I propose below, may be able to further enhanced but here is a working example that has been tested and does provide the results you are looking for in a float so 1.5 is possible when averaging off the final compute.
Here is the form:
Here is the Flow
Here are the actions and expressions:

if(equals(variables('Q1'), 'Oustanding'),int('5'),if(equals(variables('Q1'), 'Beyond Expectation'),int('4'),if(equals(variables('Q1'), 'Meets Expectation'),int('3'),if(equals(variables('Q1'), 'Below Expectation'),int('2'),if(equals(variables('Q1'), 'Issue'),int('1'),if(equals(variables('Q1'), 'Unknown'),int('0'),''))))))

if(equals(variables('Q2'), 'Oustanding'),int('5'),if(equals(variables('Q2'), 'Beyond Expectation'),int('4'),if(equals(variables('Q2'), 'Meets Expectation'),int('3'),if(equals(variables('Q2'), 'Below Expectation'),int('2'),if(equals(variables('Q2'), 'Issue'),int('1'),if(equals(variables('Q2'), 'Unknown'),int('0'),''))))))

if(equals(variables('Q3'), 'Oustanding'),int('5'),if(equals(variables('Q3'), 'Beyond Expectation'),int('4'),if(equals(variables('Q3'), 'Meets Expectation'),int('3'),if(equals(variables('Q3'), 'Below Expectation'),int('2'),if(equals(variables('Q3'), 'Issue'),int('1'),if(equals(variables('Q3'), 'Unknown'),int('0'),''))))))

div(add(add(variables('A1'), variables('A2')), variables('A3')), variables('Divider'))
If implemented as above for 3 questions it works. You would need to scale out to suit you.
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Thanks, Alan