Issue Creating a Managed Package from a Dev Hub Org

I’m currently trying to create a Managed Package from an enabled Dev Hub Org

, following the  

Salesforce documentation for registering a namespace: 

https://developer.salesforce.com/docs/atlas.en-us.sfdx_dev.meta/sfdx_dev/sfdx_dev_reg_namespace.htm

However, I consistently receive an error when trying to complete the configuration/create the managed package.

I would like to understand the following:

1. Is this error related to the Spring ’26 Connected App changes, specifically the restriction on creating new Connected Apps?
2. If it is not related, could there be any missing or incorrect configuration in my Dev Hub Org, namespace, packaging org, or user permissions?
3. Is there any updated Salesforce-recommended process for creating Managed Packages now that new Connected Apps can no longer be created?
4. Is there an alternative approach or updated documentation that I should follow for creating and managing a package in the current Salesforce release?

I have already enabled Dev Hub

and followed the namespace registration steps in the Salesforce documentation, but I’m still unable to proceed.