It is definitely a dilemma. Unlike Order versus Chaos which has a clear and skill based game from both players where you can punish mistakes, Order versus Elementals is very lop sided and I can't give you any magic bullet advice because there is none.
-game starts, order goes archer start, ele goes earth start, order takes centre and ele Castle airs.
Literally nothing else for you to do here because that castle air is so strong. You can at least keep your archer near Ele's base (but out of range of the Castle Air and not able to attack Ele's miners) so Ele is less likely to bring their first Tree to mid due to how many times you would get to shoot at it before I roots and starts with Scorplings. Once Ele has one tree rooted, Ele is going to want to put their next trees near it, so you can incentivise Ele to build Trees as far away from your statue as possible instead of closer
-order goes for miner archers with some swords to try to break ele economy, ele goes miner spam and hustle. Order is unable to do much damage to ele, because they can build miners much faster and can hustle much faster.
I don't see the point in even trying to buy swords to attack ele's economy here. You're very unlikely to kill much because the castle air chunks so badly and Ele can create a charrog very quickly when Ele sees it needs protection - and Earth spam works as protection often enough, and can then convert into eco anyway. You may want to try committing what would have been swords into miners and consider walls/castle archer if Ele becomes very aggressive quickly. Swords aren't going to press into Ele once Ele has a single tree out, and Trees are cheap.
-ele stacks gold/mana, and goes for a tree, followed by 2 more in quick succession. At this point order has like around 4 archers, some swords and a healthy eco to spam out sword archers.
If order tries to rush ele with tower spawn + rage swords or just a huge sword archer rmass, ele can hold with castle air or spawning healthy trees to protect their weakened ones. If order fails this attack, (which has a very small window to succeed), they are screwed and will not have enough resources to turtle.
Yep
if order tries to mass archer Merics, ele, with the aid of 3 trees and charrog/Tower spawn, can force order off tower and force orser to turtle, where the spells can kill the archers/miners with no space to retreat. So going on offense is not a good option.
I presume by spells you mean Inferno? Both of its spell casts are slow and predictable. If you mean Charrog then I presume you're getting attacked without having a wall up.
I think it's worth reiterating that Order is almost certainly in a weaker position here. Your economy will be weaker, and you will have to start praying to advance much further up the tech tree (and Ele doesn't have to) and Ele is bringing out trees and able to swarm at you with free Scorplings. Ele can probably hold tower easily on smaller maps and there won't be much you can do about it other than slight archer damage all the time.
The good news is that Charrogs have awful dps, and Scorplings die quickly to castle archer splash. You could try not having as many swords and instead having Castle Archer and walls, or if on a long map with Ele's trees close to their base, focusing on almost all archers instead and keep kiting to avoid taking any hits then running forward again after the scorplings are dead to avoid giving up too much ground, at least until you get forced into base defense. Buying swords to tank Scorpling damage is not as cost effective as walls, and I don't see you successfully killing a Tree even with rage once there's 3 of them.
-if order turtles with spear meric into mage ninja and giant, they will most likely fail too. Because 3 trees + tower spawn + spells can put tonnes of pressure on order at the spear meric stage. When orser gets a mage, ele can use v to kill it, order won't have a ninja by then. Or ele can spam cycloids in such numbers that they can wreck miners, Merics, everything. Order's pop will go down until they have nothing left.
What I've done before, in situations where I know I can't afford to research and then buy a ninja but really need the mage is to buy the mage, keep it in front of my archers and buy the poison spell only. When I have 3 or more Merics, the poison spell isn't going to hurt me too badly if Ele brings out a V and steals my Mage, and I will have enough notice and Merics before the Mage can cast the explosion spell that I should be able to avoid losing too many archers to it. With the deliberately handicapped Mage I then keep poisoning Ele every chance I get, because Ele has no cost effective way to cure poison, and Ele has so many low hp units that the poison ticks hurt a lot more than they would on Order or Chaos. The other great benefit to making Ele have to sacrifice waters on healing is that it stops Ele from using them to make Trees, Cycloids and Vs. Casting the poison spell as Ele approaches also ensures it is on cooldown before Ele can use a V on your Mage, and if timed well can poison the entire front line.
I think after you lose, consider what units you bought that never achieved anything. And see if you remembered to buy Hustle yourself, while you were dealing with Ele. I find personally it is easy to get caught up in slowly losing the game of offense and map control that I forget about economy.