I have a question because recently I had to implement a way to expire static assets and I would like to hear creative/new ideas.

For example, I have all my static assets on S3 and I want to generate a link that will make data available for a long time (let's say 1 year) but with S3 signing you can only generate a link available for a week max.

How would you go about doing this without relying on another server?

I think this is what happened with the public bucket. They thought about how to deliver static assets without relying on a server and the only way they found is to make the bucket public.