Play as Rusviet-Industrial. You may have to uncheck "Prevent banned mat combos" when starting the game. I used 2 medium bots, but I didn't interact with them except for winning a combat against a lone mech.

1. Produce
   
2. Produce
   
3. Produce & Deploy speed mech on the village (worker star)
   
4. Move 5 workers to the oil and 2 to the iron - iron tile should have 3 total workers. Take the encounter; just take the 1st option. It won't really effect the strategy.
   
5. Produce/Deploy
   
6. Produce/Deploy
   
7. Bolster/Upgrade - upgrade bolster to get extra power
   
8. Produce/Deploy (mech star)
   
9. Bolster/Upgrade
   
10. Bolster/Upgrade
    
11. Bolster/Upgrade
    
12. Bolster/Upgrade
    
13. Bolster/Upgrade (upgrade & power stars)
    
14. Move to win 2 combats or move to complete 1 objective & 1 combat
    
15. Finish objective/combat stars if you didn't last turn

The Bolster-Produce chain can be done in any order. I guess Upgrading first would give you a higher score as you use less metal for Deploying mechs.

Credit reddit user Horist for the strategy.