I feel like maybe this problem was "solution first". A cronjob is a solution. For example, Supabase supports cronjobs, but it can't be used to take screenshots.

This might be a non-answer, but if you just want "scheduled notifications of a website change", then you can use something completely purpose built for that. There is a Github action that does exactly this: https://github.com/yasoob/github-action-scraper-tutorial/blo...

This might also be a non-answer, but I've found myself using Integromat/Make or Zapier more and more for this type of work. It allows me to whip things up quickly and it can actually be approachable by non-technical people.