Pavement-focused (80%+ roads): Road bike. R11 or R12. Lighter, faster, more responsive.
Mixed terrain (roads + gravel regularly): Gravel bike. G21. More versatile, capable, stable.
If you must choose one: Gravel bike. It handles more terrains adequately than a road bike.
Most riders genuinely only need one bike. Choose based on your actual terrain split.

Carbon frames require minimal daily maintenance but benefit from careful handling — always use a torque wrench for bolted connections, store in a climate-controlled space (15–25°C, 40–60% humidity), transport with frame protection at contact points, and inspect thoroughly after any impact. These simple habits protect a frame for 10+ years of riding.