Question about Fairphone 4

Hi, I've had a Fairphone 4 since January, and the system is suggesting that I update to Android 13. My device has just come back from repair, and when I install the update, it's impossible to switch the phone back on, a screen suggests you try again or go back to the factory settings... I've done this 4 times and always with the same result. I also get a notification telling me that my system is out of date... I don't know what to do, because I really don't know anything about phones... But I have to admit I'm surprised that a phone that's just come back from repair can't update itself properly and that they haven't installed the latest update as part of the warranty...