Honestly, for most desk carry, a simple pen with a good battery and airflow dial is all you need. You don't need a box mod or a fancy screen. Keep it cheap, keep it reliable, and keep it clean. If you're only using it a few times a day, you'll never miss the advanced features.

A good rule: if you're thinking about it, you're overthinking. Start with a basic device, learn how it behaves, and upgrade only if you hit a real limitation.