I appreciate your enthusiasm, but I’d rather spend time getting the PR through OpenWrt than review of a clone.
On why is it not there, it can be attributed to the lack of a meaningful process to review and merge non-trivial contributions.
After four months now, there has been a commitment of merge pending removal of the work to ensure seamless upgrades. I have spent two days testing the results across dozens of upgrade combinations based on that commitment. Remaining at this time is reworded commit messages to reflect the removal of the smooth upgrade process and a push to GitHub.