As someone who is currently using a fairphone 3, I cannot recommend it.
The idea is good, but let down by very cheap hardware. The fact is that, when you get the phone brand new, it’s already a very low end phone. Still having it 3 years later just means that it’ll be even worse. The fact that you can repair/replace most of it (but not upgrade) doesn’t change that fact.
I have been so disappointed with the experience on mine and would’ve replaced it ages ago if I could afford to.