oidfjgxccawqe One of the most important security features of GrapheneOS is the ability to lock the boot loader and the provide roll back protection. So no, it's not possible to roll back. Only chance is to reinstall GrapheneOS manually with an older release, but then you loose all your data and then you don't get new security updates or security features.
Nothing in this world is perfect, but the developer team is doing the best they can. In the meantime we can support them with monthly donations and spread the word about how great GrapheneOS is.