Not being an expert, but having some experience with the OP6 that I use as my daily phone and have upgraded from Android Pie to the “R beta” version, I would say that you may have the problem of doing an update on an e-os-r installation without coming from a suitable stock rom.
I followed the advice of @chrisrg who managed to upgrade to the “R” version by updating to OxygenOS 11 using the stock update tool and then sideloading the eOS ROM. See the detailed discussion here.
I started from an earlier stock rom and followed advice of @kopap by extracting the various images from a payload bin and it worked perfectly as I have able to update to the very latest e-0.23-r-20220514185543-dev-enchilada.zip and there have been none of the issues evoked in this discussion.
Hope this might help.