Unfortunately extension support on iOS is still a work in progress. As you can see, there are over 2000 other issues so providing support and assistance for a private extension is not a priority for the Orion team. It looks like you have taken the intended steps for installing the extension, but the outcome was not desired.
I'm afraid there is not much else for you to do now, and I hope a future update will add the support for the extension you are attempting to install.
