I hope no one has asked this before and i just didn’t manage to find it.
So I got a new FP5 and transferred my data from my phone beforehand on to it. Sadly, it also copied my default sounds.
Go to the app Settings
Go to Sound and vibration
Go to Phone ringtone and choose your ringtone (I have Sunbeam, that’s more of less the ‘official’ ringtone of Fairphone)
Within Sound and vibration you can also choose your Default notification sound and the Default alarm sound.
Mind you. There is only 1 stupid question. That is the question you don’t ask.