I've been using DigitalOcean App Platform for a while now. It's not a 1:1 Heroku replacement, but the git-based deploys, managed DBs, and ability to move to Droplets later without a big migration have worked very well for me.
Many people are saying that ChatGPT or Copilot could write great scripts which is indeed true, but the eBook was written way before those LLMs were a thing. It is still good to learn the basics though.