Kobo is actually in the process of completely rewriting their e-reader software (you can download the beta in the EU), and I’m pretty sure it’s no longer based on RMSDK. Adobe basically handed the EPUB DRM market to LCP on a silver platter by being a poor maintainer and then selling off to a third party that had botched the migration and further angered end users and platforms, that are switching off Adobe faster than ever
Have you tried the beta? Have you found it to be substantially better?