So for ♥♥♥♥♥ and giggles I was browsing info about this game and I came across the IMDB page. So it shows a ton of voice actors, as in separate ones for each class. But when I play the game all I hear are the same two guys for GDF and Strogg. So what's up with that?

Most probably different localizations. If you include console releases AND Asian freemium release, Quake Wars had full audio support for 8 languages.

English

French

German

Japanese (only on consoles and Quake Wars Online)

Korean (text only on ETQW, full support on Quake Wars Online)

Polish

Russian

Spanish
https://pcgamingwiki.com/wiki/Enemy_Territory:_Quake_Wars#Localizations
As I play the English localization, I believe there's 3 or 4 voice actor.
1) Female voice actor of opening cinematic.
2) VO (announcement) voice actor for GDF, Strogg and tutorial.
3) GDF character voices.
4) Strogg character voices. (that's probably made by the same guy from 2 or 3)
Multiply this with the number of localizations, you end of having many voice actors.