Have a look at their impact report. They themselves claim that they don’t spend more than €5 per phone on fair trade or environmental stuff.

You are only paying more for that phone because they are a tiny boutique manufacturer who has to outsource everything. The fair/eco stuff is just fair- and greenwashing.

If you buy a phone because you want to look fair/eco, buy a Fairphone. If you actually really care for fair/eco, get an used phone and donate some money to the correct NGOs or charities.