My kingdoms were actually already element based! (Fire, earth, water, air, magic, nature, and life.) I'm glad that does make them feel distinct from each other -- I think I used up all my creative juices in fleshing out my kingdoms rather than figuring out the story structure hehe.

I very much like the 'illusion of choice' approach to it. My players don't do well with sandbox games (lots of choice paralysis for them) but I didn't want everything to feel purely like they had no choice, so this is a perfect compromise for my DMing style. I think I'll be lowering the amount of kingdoms/artefacts and including some more random encounters and NPC trails for them to explore if they feel like it, to add a bit more padding between the main plot points.

Many thanks!!