2v2 late game pn cataract is almost mainly flag hunting, if you lose one portal it is very hard to come back in a 2v2 (cataract). Because there are three important flags that you have to protect. If you don't have two dg's that has aoe it's hell. Because hard to hold the flag against another dg locking it. most of the time that DG and giants will be too much to tank. And the other dg is kept busy among valor and portal and giants eventually start bashing mid. Thats how most games end.
1-If you are not on vent or if you don't know your partner well enough, there will be the problem of communication. If that's the case, sometimes it is best to pre-decide on a strategy. So each one of you pick a side and protect and push that . You are responsible of that lane's threats and portal pushes. Or defensively determine which dg is gonna hold who. so you are playing as oak, tb and enemy is sedna, ub. It might be good to think of who is gonna take care of who. If ub rushes for your portal, always oak teleports if sedna rushes it is tb's job. This can all be told in one line and i think that helps. Example: I hold ub. this is the defensive aspect.
2-well if the portal is gone and if both teams are playing correctly. All you can do is to play the teleport game , this is the period when you watch your enemy teleport times more carefully. Now you have to draw attention make enemy port and fake-port to fight in your portal outnumbered or force them to fight after they lock the portal and eventually find a good time to turn into yellow when the enemy is outnumbered.
This usually happens at some point if the items are balanced. because if you lock the flag and fight a short while. You will not have enough time to recharge and teleport back to lock it. So forcing the enemy to fight a while where your distance is shorter to the crystal is usually helpful. They might decide to stay for relocking but then it will be harder for them to fight without full hp. Either way it is to your advantage.
Oak is an exception to this. He can just safely lock the portal, kiss you on the chick, port out and come back for another round. So go for their portals and play tricks so he just fuckin stops doing that.
Regarding troop upgrades. My personal strategy is usually" I like mine being better than theirs". So watch the upg they have on their giants(their hp) and get a better upg. i think it is quite helpful to have your troops have a slight advantage over theirs unless there is aoe madness on the oppoenent team. If the aoes are about the same on both teams. You are likely to gain some more vision on the map( it is important after towers are down) and if the enemy giants are pushed further away to their side when they fight for 2 mid section flags, they will get the extra bash from your troops. But yeah, after 1st upg of armory and bs, always get the journey and the basic need first.
well everything is quite situational so actually this can all be summed up as late game map awareness is more crucial.
Random Dg history in 2v2s: There was sakke and erska back in the day and they played a mean speedy oak,sedna combo. They just ran around flags and spammed abilities. Almost never engaged and was very hard to deal with.They were brothers from Scandinavia in RL and played quite in their own style. I always thought that was seriously cool.Oak, sedna combo along with ub, sedna combo eventually failed against the ub, oak combo.
I think i am lost in this. So i am just gonna end it here.