Hi,
It looks like you’ve done a lot of debug to look at updates, so my suggestion would be to post a linked GitHub issue for the ZHA folks to look at.
I posted here, then raised an issue, and the devs were quite helpful (likely as we’ve both done the leg work and not posting something trivial).
The only thing I can spot comparing your ZHA configuration.yaml snippet, is yours has a path, whereas mine doesn’t. Mine did have a custom quirks path, but once the release was made, it wasn’t needed so got removed.
# Manual config to enable Zigbee firmware updates
# https://www.home-assistant.io/integrations/zha
zha:
zigpy_config:
ota:
ikea_provider: true # Auto update Trådfri devices
ledvance_provider: true # Auto update LEDVANCE/OSRAM devices
salus_provider: true # Auto update SALUS/Computime devices
#otau_directory: /path/to/your/ota/folder # Utilize .ota files to update everything else
# https://github.com/zigpy/zha-device-handlers/discussions/693#discussioncomment-857274
#custom_quirks_path: /config/custom_zha_quirks/
Note that even with things all confirmed working, an upgrade takes about 1-2 DAYS. Although my 5-button remotes have had good battery life for about a year, I’ve still got a new 2-button IKEA remote that doesn’t pair with ZHA so not everything works!
If this helps, 
this post!