Maybe it's just me, but nothing sounds simple about offline mode. The changeset resolution necessary to resync after going back online sounds TOUGH to build in a way that doesn't result in user data loss ever without being more cumbersome than it's worth.

I remember Notion talking about adding this YEARS ago. It has literally taken them YEARS to build this. So yes, very complex

I'm on a team building offline mode into an enterprise product at work and you are soooooo correct about this. Offline mode is a deceptively hard problem to begin with and it becomes 10x harder if you're trying to add it to a product that wasn't designed with offline mode in mind.

The best way to do it is right from the start. It's hard enough as is but adding it on after the fact is even harder.