This discussion might be interesting to you:
Amongst others I myself shared why SHIFT wouldn’t be an alternative for me. To be fair (pun not intended!), they have by now released their sustainability report (see the posts more to the bottom of that topic).
Since Fairphone soon will release Android 6 for FP2 and they are working on a camera upgrade, they won’t be releasing a FP3 soon. There haven’t been any announcements made about a FP3. A FP3 would basically mean a phone with a new chipset because that’s the only part of FP2 that cannot be replaced since the other modules depend on the drivers of the chipset.
Furthermore FP2’s technical specs aren’t so bad and you will be happy with it, if you don’t play heavy 3D games. Compared to FP1 it is a major improvement and I’m always amazed about how snappy FP2 feels when I hold it in hands (I’m still with my FP1).
Edit: What do you miss in FP2 compared to SHIFT5pro?