I've been building https://notionbackups.com for almost 4 years now.

It's mostly feature complete at this point, but there are still some rough edges.

Notion's API is far from complete, and updates are few and far between. This has led me to work around some of its limitations in creative ways. For example, there is still no way to create top-level pages in Notion, which makes restores impossible. Instead, I ask customers to create a top-level page themselves and write backups there.

Personally, the hardest part of working on a project for an extended period is not getting burnt out repeteadly. Sometimes it helps to work on something else, and other times you just need to step away from the game entirely for a while