Vaccinated with Pfizer or Moderna, any differences in safety (from a covid perspective) are statistically negligible. Wash your hands and follow the local mask guidance and you'll be fine.

Unvaccinated, I'd probably hang out in a part of the terminal with high ceilings and fewer people, but within earshot of my gate. Easier said than done in some places... After that, I'd rather be on the aircraft. Lounges would be my last choice. They're usually crowded with people eating and drinking and don't always have high ceilings or great ventilation.