01
Format is not mode
A 3v3 format describes team size; Annihilation describes the rules objective. Keeping them separate makes the current answer easier to use.
02
Prepare with the shared loop
- Build a base and contest resource points.
- Use cover and retreat to preserve squads.
- Reinforce in the field and protect veterancy.
- Choose a faction by confirmed identity rather than a pre-release ranking.
03
Still open
The complete map pool, matchmaking parameters and live balance relationships are not established by current sources.