Whichever you're more curious about! There's plenty of opportunity available in both directions and there will be for a while still. And as your career matures,

Whichever you're more curious about! There's plenty of opportunity available in both directions and there will be for a while still. And as your career matures, you'll be pulled in still other directions: domain specialization, breadth-building, etc. There's no optimal choice, it's just personal. The most valuable thing you bring to your career right now is enthusiasm and curiosity. Lean into that by picking something you like.