[PC][2000-2006][FPS] ARMA-esque game involving aliens and humans, looks like HALO CE "Silent Cartographer" mission

Platform(s): PC

Genre: FPS

Estimated year of release: 2000-2006

Graphics/art style: Similar to HALO CE

Notable characters: /

Notable gameplay mechanics: /

Other details: Maps were islands with lots of heights

Hey hey people,

I'm currently playing the "Silent Cartographer" mission from Halo CE and I distinctly remember a game from between the 2000-2010 with a similar look & feel like that mission. It involved suited up humans vs aliens on large islands and you had a few squads you could give orders while you were running around. There were some vehicles and I very vividly remember a troop carrier that was the spitting image of Halo's Pelican. But it was much larger on the inside and you could run around in it.

I was too young to really remember a lot of it, but I hope someone could point me in the right direction!

Many, many thanks! <3