Hi @Klaitos ,
You can customize your project ID as mentioned in the Deploy to Firebase Hosting documentation. You may also check Deploy to live & preview channels via GitHub pull requests for guidance on integrating Firebase with GitHub.
As for the GitHub deploy preview failure, there are a couple of things that might be causing the hiccup. The 404 error in the artifact repository usually means that the specified artifact is either missing or has already been deleted. Also, if your Cloud Functions are hitting time limits or running into errors during execution, that could lead to deployment issues as well.
If you continue to run into issues, consider reaching out to Google Cloud Support. Their team is great at diagnosing underlying issues. When you contact them, be sure to provide as much detail as possible and include screenshots. This will help them understand your problem better and get it sorted out more quickly.
Hope that helps!