Just finished it, too. 

If the Quest is discontinued, almost all the content is available @ the Trail: https://trailhead.salesforce.com/content/learn/trails/get-started-with-ai-data .

To make the Quest they added:

• the blog-post https://www.salesforce.com/blog/learn-ai-skills-on-trailhead/

before and 

• https://www.salesforce.com/news/press-releases/2023/06/12/ai-cloud-news/ , 
• the link to the Einstein Community for you to join (https://trailhead.salesforce.com/trailblazer-community/groups/0F94S000000Gw6dSAC?tab=discussion&sort=LAST_MODIFIED_DATE_DESC) 
• and having you share your learning here afterwards. 

For some reason (?) they took out the Data Fundamentals for AI module for the Quest, though.