There is no pressure on kids, other than their idiot parents. School should be seen as trivial and boring, because grades don't matter. Grades don't matter because if you're not an idiot, you can flunk school and do well in life with minimal effort. Just try many things to see what you like and then do it for 10 years.
If it's athletics, you can go work a physically demanding job that pays well. If it's an intellectual pursuit, you'll be well suited for university and a high paying job. If it's creative, the admiration you get for your art will matter far more than living in a basement. If it's just being a nice, easy-going, kind human being, quality relationships will matter more than living in a basement.
Whichever way you go, you win, unless you have idiot parents who teach you to be unhappy and insecure, like them.
Another aspect of it I was reminded of today by a good twitter post (I went back looking for it but it has disappeared from my feed!) has to do with sources of value. It was basically theorizing that lot of people who end up running into issues with generalized anxiety and depression as (young) adults, do so because they place all their self-value in their work and accomplishments (socially defined). He was cautioning people against viewing themselves exclusively as creators of products (in a general sense), and only valuing themselves as such. It's a common trap for folks sort of over-embracing capitalist ethos.
Maybe just making it known that it's _okay_ if they are 'merely' an ordinary person. I bet a lot of this isn't even verbal, but just comes down to whether parents actually are or are not okay with their kids being less than extraordinary.
If you're aware of the issue you're probably already fine though--the rest will follow from that.
(Of course I'm not a professional of any kind on this matter, so, you know--generous grain of salt!)
I’d try to frame test as purely information-gathering. There should be neither penalties for low grades nor accolades for high grades (those are for dangerous things and showing initiative). Instead, use the grades to adjust study strategies- are their high grades because of a natural affinity or spending too much time on the subject? Are their low grades from not putting in enough time/effort, not understanding the fundamentals, not finding interest in the subject, etc.