Data connection failure on EE UK after FP3 Update 901.4.A.0019.1

Yes that is what I meant, sadly it hasn’t been that simple for you.

You may want to try updating the APN settings.

Do you have just the one SIM and do you have a PIN on in it?

There are many posts on resetting the APN, but I’ve never had to do it.

https://forum.fairphone.com/search?q=APN%20FP3