Update: problem is now resolved and the dac8 is working again. I note that the guide for configuring the system in the Volumio iOS app is not very clear: you can’t manually assign a network, it’s impossible to write in a name/ip-number since the pop-up closes all the time. What you are supposed to do is go to the next step (without assigning a network), then suddenly it all works again. Probably went through since I have an open network that doesn’t require a password. Not so smooth.
Furthermore: I suggest that there should be a warning coming up when your system won’t play, not just this ‘alsa’- message (and only under international radio stations, no such thing using spotify in the volumio app). And then somewhere there should be info on the necessity as well as how to produce a log to send to volumio support.
Thanks everybody for your help. Music is back again. Now it’s just to force spotify to deliver high-rez/loss-less audio promised 2021, and qobuz to make that connect feature they also promised.