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:
Attempting to remove the user who initially configured Entra resulted in an error " This user is an owner of the assets listed below. We recommend adding another owner before the user is deleted. Otherwise it might be difficult to determine which assets need more owners assigned to meet your organization's policies".
Solution:
Issue resolved by @Peter Parker
Being a member of the Global Admin group. They discovered that they were missing the "Access management for Azure resources" permission. By changing this permission to "Yes", the user was able to resolve their issue and gain the necessary permissions to manage Azure resources.
If you have any other questions or are still running into more issues, please let me know. Thank you again for your time and patience throughout this issue.
Please remember to "Accept Answer" if any answer/reply helped, so that others in the community facing similar issues can easily find the solution.
Thanks,
Navya.