This did the trick. So we have a faulty configuration here. Thank you for your support.
Summary
Machine with the issue:
Acer Chromebook Spin 514 (CP514-1H, CP514-1W) with Hardware ID EZKINIL.
Firmware replaced by mrchromebox’s full UEFI (full ROM), so it is basically a non-Chromebook Notebook now
Picasso Ryzen 3 CPU (3000 series)
I installed a Fedora 42 Workstation test system on an external drive. Without running any updates, sound worked fine, but power management struggled a bit. I was unable to adjust the screen brightness and the fans where on full speed all the time.
After applying the latest updates, audio broke and internal speakers did not work. The only audio device I got was the dummy output.
I again got
acp3x-alc5682-max98357 AMDI5682:00: ASoC: driver name too long ‘acp3xalc5682m98357’ → ‘acp3xalc5682m98’
in my kernel logs.
So I perfectly reproduced the broken state of the machine. That was what I wanted. 
Applying the RPM below did the trick and after a reboot I now have crystal clear audio on that machine.
alsa-ucm-1.2.14-3.fc42.noarch.rpm
Thank you for everyone helping me out. Next step to do is writing a bug report, right?