[NeutronBoy]

I run a static blog on S3 using Lambda. I upload a markdown post to an S3 bucket, Lambda runs Hugo (could be Jekyll, or whatever) to regenerate the appropriate files, then uploads it to an output buckets, invalidates the files it needs to in Cloudfront, etc.

Not infeasible to think you could use Lambda to generate a static cache of a WP site onto S3 and update files on demand.