For this post I'll assume you are talking about 1v1 gameplay.
Yes there is a minimum threshold of APM required to respond to things happening in the game.
No it is not starcraft-tier. By all accounts, zero-k is a game where you do not need APM to win.
When people talk about APM in RTS games, the gold standard is esports tier starcraft. In those tournaments, you'll see players bost high 200 and mid 300 apm, where that means players are doing about 300 keypresses and mouseclicks per minute, or about 5 per second. A lot of this APM is rythmic in downtime, shifting the view of the camera, re-issuing move orders to the same place on the map, setting and switching between control groups in set up for explosive bursts of combat. Once combat rolls around, the high apm is used to carefuly move different groups of units, cast many different spells at the same time, or any other very useful things which are required to eek out an edge. But even durring combat, there are required economic actions, like producing more marines, or building a new base. This is absolutely required in starcraft, because you need to wait unill you have the resouces to queue actions, and you are accruing resources while you are doing combat things. This is where starcraft becomes an apm nightmare.
Zero-k is much more different than starcraft. Units have a lot more 'lag' to their movement, and can fire while moving and without issuing orders. Weapons in starcraft are instant hit and often issued commands target the closest unit, which makes 'blink micro' a very valuable tool, where a player needs to select a specific low health frontline unit and remove them from the front line of combet to protect their firepower, and this requires a reaction time of less than half a second to do optimally, and is a routine occurrence. A lot of things happen instantly, like weapon damage, the blink, movement. In zero-k, weapons are physics based, have a travel time, movement requires a unit to turn and accelerate, cannons need to face the right direction before firing. In zero-k, there is absolutely an advantage to paying close attention to these things, so that you can dodge projectiles and win trades. But zero-k has a lot more warning for the player before this needs to happen, due to the presence of radar, and the general speed of units and line of sight. And primarily, you can queue actions for your economy well before combat happens, and you don't need to touch it during combat.
This is a lot of words to say "the game does not require a fixed schedule of inputs like starcraft. Because there's not this fixed schedule, zero-k is a less apm focused game." So you should think about how you're going to accomplish all the things of top-level play at a more slack pace.
Actionable adviceUse the mechanics of the game to help you macro more effectively.
Be cognizant of energy expenditure and your energy scaling, i.e. your fundamentals in economy. If you build units that spend e like planes, shields, cloak, be sure to have extra energy. Have extra energy for reclaim and repairs when you're doing that.
Understand the construction priority system.
https://zero-k.info/mediawiki/Economy_Guide#PriorityWhen you understand priority, know that you can leverage Resource Reserve.
https://zero-k.info/mediawiki/Economy_Guide#Reserving_resourcesLook into Default unit states. There are many useful options that you should set, like factory assist.
https://zero-k.info/mediawiki/Unit_states#Factory_AssistI use factory assist on all my factories by default and expose the toggle in my UI. Often, I'll have 2 constructors by my factory chilling and assisting it, so that when I want new free cons I will queue 2 more and take the 2 that already exist, so it's always on-demand. I do not need to schedule "build cons, in 10 seconds give them orders" in my brain, just "build 2 new cons, move the ones that exist" in one smooth action when I need to build mexes.
I have a hotkey to set build construction to high priority. When I want a turret, I use that hotkey on the building, often in conjunction with resource reserve. Hotkeys/instant/set high priority
https://zero-k.info/mediawiki/Unit_states#Build_Priority90% of the time when I'm building from a factory, that factory has repeat queue. I set a queue of a mix of 1-3 units, like dart-scorcher-fencer or ronin-ronin-ronin-ronin-reaver. I use alt-click to build single units, for example if my queue is glaive I will alt-queue in 2 reavers and a conjurer, so that my factory returns to infinite glaive. When I feel that glaive is countered, I click on my factory, use the stop command (I have it bound to ctrl-s) to clear the queue, then start a different queue, like some ratio of ronin-reaver, ronin to kill the counter and reaver to anticipate the raider response.
You need to set your mindset. You need to be able to think about multiple things happening on the map "at the same time". Every attack vector you can strike, every attack vector you can be hit from, and your economy. Try setting a mental 30-second timer in your head "I should think about my economy", and make sure you back off your frontline dutties and asses your economic concerns: need to build energy?(yes at least a solar) Are there metal extractors you need to take? Is there a juicy reclaim field you should send cons to? Does your factory need more plates/caretakers?
When a frontline constructor is being approached by an enemy, and it has a long command queue, and you can intercept the attack with nearby units, issues a new order to the front of the constructor's command queue: Move away. This should preserve the queue you spent time clicking before, while you can then micro the fight part of the game and push the enemy back. You can issue this order by holding down spacebar while right clicking in the path of desired retreat. Example: I have a mason on comet catcher that has a queue to build 5 mex clusters with solars and llts on them, and it's being approached by an enemy kodachi. I have 5 scorchers in the vicinity, but the kodachi will reach and attack the mason before I can intercept. I space-click issue a move order on the mason towards the scorchers, and I micro the scorchers to scare off the kodachi, while managing other fronts in a zoomed out state. I can safely ignore the mason, which will continue on it's mex building queue safely, or I can cancel that move order by re-issuing a move order on the exact same place to cancel it and optimize the mason's travel time. I do not have to spend seconds re-issuing the queue.
