The lowest carbon way is also probably the cheapest way. I dunno, maybe a static site on the cheapest s3 tier (with reduced redundancy) using cloudflare's free tier (workers, CDN, DDoS protection, SSL).
https://cloud.google.com/sustainability
EU based smaller hosting provider such as scaleway:
https://www.scaleway.com/en/about-us/
For website, static generation opposes to loading ton of javascript and using a cdn.
Not much to go on here.