No, it is an open issue in Debian.
We (openHABian) retrieve openJDK from the unstable Debian repo. It is located only there because it is not yet considered to be stable by Debian developers and @stefan.hoehn what you see is stuff that happens (and will continue to) all along the way when some complex software combo like a Linux package or even OH to rely on it is on its journey of maturing.
You can attempt to install Temurin for the time being.
But AFAIK there is no Java 21 package available yet that can be considered to be ready for prime time. So
this clearly is not right.
Sure: as a dev to handle your OS-Java-whatever prerequisites yourself you’re okay with that.
As a general recommendation for other devs - no. Let alone for users.