It’s no secret Apple refuses to repair items where the warranty has been invalidated. It’s fairly standard here you often see ‘Warranty void if removed’ stickers on all sorts of electronic products.
Here’s probably the most famous video about it - they took apart an iMac Pro …and broke it when trying to put it back together 
I think common sense needs to be exercised, and as far as I know Apple allow people to change RAM in iMacs and Mac minis without it validating warranty 
I think you missed the point 
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Be more clear then 
Here in the UK goods purchased have to last a reasonably expected time - that’s about 6 years for electronic devices. Apple even recognises this on their website:
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