I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to "Accept " the answer.
Issue:
The Copilot iOS app fails against Conditional Access
Solution:
Issue resolved by @Gerry Murphy
MS is moving all of the copilot features into the Office app, so there is no standalone app any longer.
Sharing an article for reference: https://zcusa.951200.xyz/en-us/windows/client-management/mdm/policy-csp-windowsai The link to turn off Windows copilot is explained towards the bottom of the article.
The entry point for copilot is now the 365 app. That is what you need to set to the policy around. There are a bunch of changes going with this now https://techcommunity.microsoft.com/blog/windows-itpro-blog/enhanced-data-protection-with-windows-and-microsoft-copilot/4246428
If I missed anything please let me know and I'd be happy to add it to my answer, or feel free to comment below with any additional information. Thank you again for your time and patience throughout this issue.
Thanks,
Navya.
Please remember to "Accept Answer" if any answer/reply helped, so that others in the community facing similar issues can easily find the solution.