It is easy using standard static blogging framework like Hugo/Zola + Cloudflare Pages. I have a minimal blog (<100kb) and it meets all the criteria that OP has listed.

This is what I did:

- Use Hugo Blog Awesome theme

- Followed the 512kb guidelines and verified the page size.

- Stripped down any images and unwanted JS, but there weren't many.

1: https://512kb.club

2. https://radar.cloudflare.com/scan