I had a look at best practices for upgrades on Silverblue and you might be right, that’s something to look into. However, during my research I ran into rpm-ostree status -v and it signalled me the following:
InactiveRequests: power-profiles-daemon
I had been playing around with updating PPD manually some months ago for better battery life but I initially didn’t see it in my layered packages, as was expected because I removed it again. But apparently it was stored as an inactive request.
Removing it with rpm-ostree uninstall power-profiles-daemon cleared the way for the upgrade to work! Thanks for the nudge in the right direction 