Can you share the link where you quoted that text from? I’m guessing it means if you modify the device, i.e. experiment with the hardware itself (soldering/modifying). I doubt this includes you repairing the phone.
I doubt this too, please check their own website. They sell and distribute the phone in the EU.
Below are some of the most common reasons warranties are invalidated by merchants:
- The warranty period has expired
- The defect or part is not covered
- The product failure is due to misuse or lack of proper maintenance
- You have made significant alterations to the product, affecting its performance
However, manufacturers can void warranty even for the smallest changes and assume “that is a significant alteration”.
Hmmm, please only focus on the Fairphone website 
That would really make things easier. You’re linking to a non-Fairphone source. So everything that’s written there does not necessarily apply to Fairphone. They have their warranty/legal stuff on their own website, only that applies to Fairphone.
That’s what I think as well. Although for the best support, it’s best to order the phone directly from the Fairphone webshop. It also helps to link issues directly to your order number.
Anyway, this is becoming more like a chat now. Maybe move this to Lounge?
Yes, move it to lounge.