You are total right, my bad.

I checked out the poky dunfell-23.0.11 tag, however, the BBSERVER was still running in the background and thus using the old bitbake. 

But shouldn't meta-openembedded be as compatible as possible? I am sure this habe been discussed dozens of times and I am ignorantly not researching enough.
At least in this case I do not see a compelling cause to use the new override style, that might potentially break older poky/newer oe combinations. 

Nevertheless, this is a non-issue for me now and the patch can be discarded.