Thanks, Umberto. No, I didn't answer yes to "remove Addon Manager" because I had multiple MSFS products installed that were still using it.
You could have just reinstall them after removing all the FSX/P3D stuff.
(I'm probably not the only one removing P3D stuff and switching to MSFS who's run into this "gotcha"?)
I don't know if you are the only one noticing this but, sure you are the only one that reported it, and it has been more than a year since we released our first MSFS product so, possibly, users are STARTING to remove P3D only now. A year ago, most P3D users were most complaining it was wrong for us to concentrate on MSFS, go figure...
In any case, thanks for your report, the issue should be fixed in today's update so, assuming you properly uninstalled all the non-MSFS simulators, the updater shouldn't try to update something for a removed sim.
With "properly uninstalled", I mean there are no registry keys left for those sims, which is what normally should happen when the uninstall completed successfully.