Anyone Bored at Work?

Used AI to improve flow of my post below.

Hi HN, I work at a nonprofit as a full stack engineer. I've been doing this for about 3 years. The work is meaningful, but not very challenging anymore — and most days I’m done in 3 hours. Occasionally, around deadlines, I might work 5–6 hours, but that’s rare.

I work remotely, and while I’m happy to be productive in short bursts, I sometimes feel guilty or "behind" when I see peers or posts about people grinding 10–12 hours a day. I don’t have any side projects or startup ideas (yet), and I’m not sure what to do with all this extra time.

I’ve been doing LeetCode and have reached final rounds at a few big tech companies (Meta, Cloudflare, Amazon), but haven’t made it past the final step. I still feel a ceiling there that I haven’t broken through.

What do people in similar situations do to: Become better engineers? Feel more productive? Use their time in meaningful or growth-oriented ways?

Any suggestions or personal experiences would really help — I’m trying to navigate a bit of an existential crisis.

Thanks in advance.