Apple Intelligence Download Didn't Complete. How to restart it?

Tried to download Apple Intelligence on a brand-new MacBook Air under Sequoia 18.1.1. -- Instead of the 4.9+ GB download mentioned in these pages, I only see 4.43GB. I can't find any way to restart or complete the download, and the AI install has been stuck on "Preparing" for two weeks. Does anyone know how to force a new download that might help complete the install? Thank you!