Toby, go through Settings/Privacy&Security and turn off all of them to begin with.
(also in the small Advanced tab on the right)
There are a hundred App "sharing" settings all turned ON by default.
Also turn off remote access unless working away from home.
https://learn.microsoft.com/en-us/troubleshoot/windows-server/windows-security/user-account-control-and-remote-restriction
Also might want to kill CoPilot Cortana and OneDrive through the Registry and Gpeditor:
It may change back with updates.
https://www.elevenforum.com/t/add-or-remove-copilot-in-windows-search-in-windows-11.5309/
Turn off 'participating':
https://www.howtogeek.com/698003/what-is-the-windows-feature-experience-pack-on-windows-10/
Make the Search feature look at your local HD instead of of opening stupid Microsoft Edge for AI search which doesn't make sense:
https://answers.microsoft.com/en-us/windows/forum/all/how-to-disable-search-the-web-completley-in/ea22410a-3031-487f-b5de-5a0113d656c5
That's a start.
Some other suspect Apps which can't be stopped because of Server Initiated Healing:
CTFloader (online translation despite only english)
UserOOBE (supposed to help find and update with initial setup only)
AggregatorHost (telemetry whether you wanted it or not)