Deinstalling a binding does never remove its Things and/or Items.
The Things will just fail to initialize without the binding being installed.
My suggested approach above should be used with caution, don’t expect it to work in general - changes in openHAB Core APIs or dependency upgrades break compatibility between JARs compiled for a different openHAB version and the used openHAB version.
For 4.2 JARs on 4.3 I am however confident that it could be tried at least to use a 4.2 JAR o 4.3, for 4.1 JAR on 4.2 I don’t think it will work, we don’t need to try it out.
As you said your issue with ZigBee were reported and are solved:
As the fix has been backported (see Commits · openhab/org.openhab.binding.zigbee · GitHub), it should get picked up by our openHAB 4.3 patch release sandbox CI build, which uploads the build artifacts to JFrog.
I would recommend to uninstall the ZigBee add-on and download the latest org.openhab.binding.zigbee KAR from JFrog.
Drop the KAR file into your addons folder and ZigBee should be running again.