I'm not familiar with Canva but I don't see any technical reason why every interaction would need to rely on the server. Since Canva uses client-side JavaScript

I'm not familiar with Canva but I don't see any technical reason why every interaction would need to rely on the server. Since Canva uses client-side JavaScript, it could be designed so that the local version of a document updates immediately and the cloud version syncs with the local version as soon as possible. I would guess Canva already does something like this.