The whole point of the fairphone is, as the name implies, that it is fair. That means that all the components/elements are sourced from (where possible) sustainable sources and all labour is paid for fairly (no 'sweatshops'). If you would rather have a flashy screen at the lowest price possible with no regard to the actual cost (human, environmental, etc.) then you can buy litterally any other phone on the market but it is great that the fairphone exists for the people that these kind of issues do concern.
Xiaomi is the essence of Chinaware: Xiaomi are hard to open/repair (environmental unfriendly), workers don't get a fair wage, materials are not fairly resourced, it has a locked bootloader, they have their own bloatware (MIUI), probably contain spyware, and likely don't even pay fair taxes.
Also, the successor of Fairphone 4, Fairphone 5, has 5G and OLED.
Also, LCD screen, really underwhelming.
I was expecting much more for that price.