Tried your method to no success. I patched using the original boot.img for my device so it's not a regional boot.img issue. Oxygen Updater app does not even allow me to check for anything other than full updates, and whenever I try to take the OTA to 2.4.4 via the official settings app, it simply says download/installation failedI took it straight through the updater, never tried to do download and local install. To be honest I'm not even sure how to do local ota because I've never tried.
Took both 2.3.3. and 2.4.4 the moment they showed up in the updater app. When I updated to 2.4.4 I tried to do it without restoring the boot.img and it failed. Went into Magisk, uninstalled by restoring images, and OTA succeeded right away.