A couple of months ago I rooted my Fairphone successfully but now the OTA doesn’t work. Which isn’t a big surprise as the signature is modified by installing Magisk. Fortunately, there is an easy method to fix this. Unfortunately, you will root your device again, but this time I was able to do it without any data loss (yeah! 🥳)
Update 24/04/2022: Works for update FF3T.A.0107
Update 01/06/2022: Successfully updated from A.107 to A.128