Thanks for sharing the detailed diagnostics and screenshot. Since updates still scan and install in the background, this looks more like a Settings interface issue with this Insider build than a complete Windows Update failure.
The Autopilot.dll 0x80070491 event may be separate, so I would not assume it caused the missing Windows Update and Insider pages.
Did this start immediately after installing build 26220.7653 or did Settings continue working for a while? Is a newer Insider build being detected or installed in the background?
One useful check is to test from a new local administrator account:
- Open Settings > Accounts > Other users.
- Select Add account > I don’t have this person’s sign-in information > Add a user without a Microsoft account.
- Create a temporary account, then select it under Other users.
- Choose Change account type, set it to Administrator, and select OK.
- Sign out, sign in to the new account, and check Settings > Windows Update.
- Press Win + R, enter ms-settings:windowsinsider and check whether the Insider page opens.
If both pages work there, the issue is probably limited to the original profile. If the same error appears, it is more likely system-wide or specific to this build.
I would avoid making further changes to the WindowsSelfHost registry keys. If a newer build is available, let it install and test again. I would also report the issue through Feedback Hub, including the screenshot, build number and Event Viewer details.
If a newer build does not fix it and the error also occurs in the new account, an in-place repair using compatible Insider installation media may be the next practical step.