This is mostly a guide for 1v1 in Zero-K.
If you compare it to Starcraft, there is never really a strict optimal economic and tech progression. It mostly depends on what your opponent is doing and how the game has progressed overall.
You should have a more fluid mindset when it comes to ecoing and so called "tech" progression in Zero-K.
Greed is good in Zero-K.
While expansion is done in incremental steps in Starcraft where the decision to go for another expansion is highly integrated into the build order and strategy you go for in Starcraft, it is much more fluid in Zero-K.
Grabbing another metal spot and making a metal Extractor there, typically pays for itself in just 45 seconds. Typically you should just expand as much as you can and retreat your constructors if you see incoming enemy units that you can't match. I recommend always having front line radars or using raiders to scout to see incoming units.
Anything you build have the same metal cost as energy cost so your energy production should always at least match the income value of metal. Then there are abilities that drain a bit extra energy like radars, cloak, repairing units, re-arming bombers or big shields. So if you are depending much on this, your energy production should be a bit higher than your metal income.
It is hard to include a prescriptive amount of energy production in your build order, as the amount of Metal Extractors you can make early game, highly depend on how greedy you can be without being punished by your opponent. There is also reclaim where destroyed units leave 40% of their metal value as wrecks that you can reclaim with Constructors or your Commander.
Overdrive is a mechanic in Zero-k whereas you connect metal extractors to any powergrid which makes them use excess energy to produce more metal. Overdrive has diminishing returns so you will have to spend more and more extra energy for every point of metal you produce.
Whenever you select an energy producing building, you will see the different powergrids on your side/team and the coloring of the these grids indicate the relative efficiency of the powergrids. Purple/pink means that the grid is not using any energy for overdrive, green means it is using a little energy for overdrive and is giving a high metal for the energy cost. Orange means, it is decently effective at converting energy into metal. Red means you are not making much metal while using a lot of energy. If the grid is red, you should definitely stop producing more energy production or grid more mexes to your powergrid in a 1v1 or team settings.
For 1v1 you can mostly ignore overdrive unless the frontlines becomes hard to break and the game drags on for a long time.
The density of units in Zero-K determines the "tech"-progression
There is an overall Rock-Paper-Scissors structure in the unit design in Zero-K.
Riots counters Raiders. Raiders counters Skirmishers. Skirmishers counter Riots.
However, in many games you can see almost only Raiders being spammed exclusively because of their speed and being able to overrun lone riots.
While Riots counter Raiders for cost, lone Riots are easily surrounded and overrun by a large number of Raiders.
However approaching a line of Riots is hard as their splash damage and/or DPS is so high that the Raiders don't have much time to get in range before they are destroyed.
On most maps in 1v1, you should simply be spamming raiders early game to try and take control of the map and counter the enemies raiders. Sprinkling out some light defenses/Lotus turrets here and there to help you defend is also usually a good strategy.
Now you might simply be able to win outright during the raider stage. If your opponent keeps continuing to spam raiders aswell, you should consider if you can get away with losing some mobility and going for slower riots to push expansions or even straight to the enemy base or if you still needs to match the enemies large raider forces.
Factory dominance and maps:
Some maps might have more or less established expansion patterns. If it is an open flat map with even density of metal points, you should consider going for Rovers, Hovers or Tanks. As their units are generally faster than their counterparts in other factories. Spiders, units that can climb any terrain, on the other hand have relatively slow units and are not suitable for flat open maps. While Spiders have a super fast light Raider, the Flea, that you can raid the enemy to death with if you have good micro, Fleas cannot easily kill other Raiders unless they can outmass them and Light Laser Turrets/Lotus turrets easily kill lots of Fleas even if you outmass it heavily.
Consider expanding through the middle of the map if the map is flat and open. That way your forces can go either side on the map to protect your expansion while forcing the enemy to attack the middle first where you can concentrate your defensive efforts.
Try be fluid in your build orders and adapt your strategy to what your opponent is doing.
Send out a few scouts/Raiders in the first minute of the game to scout your opponent. The first factory is free and you should almost always plop down the factory the first thing you do.
There is a counterrelationship/Rock-Paper-Scissors early game that you need to balance against your opponent:
Expansion -> Defense -> Offense -> Expansion
If you scout that the enemy is very defensive, you can be greedy and get away with more expansion. If your opponent is Offensive making a lot of Raiders or maybe even going for a rush, be prepared to make defenses to protect your MEXes or something to counter their rush.
What I generally consider to be greedy on most maps, is making 2 cons at start. On some maps, like Frosty Cove, where it is easy to defend, you can make more though.
I would also recommend expanding with your commander on most maps. Your commander is basically 1-2 cons and 1-2 Riots combined into one. However it also gives +3 metal income and plus +5 energy income so losing the Commander early can cripple you.