I've posted a few complaints about the node 12 difficulty - and then I did more extensive reading into the other threads on this topic. I believe I have come to an explainable situation that you may find yourself in. Here it goes.
I'm going to use my GM Yoda character for the baseline of what I am missing to maintain the previous success I enjoyed at the GW table. I used swgoh.gg and the problem became pretty apparent.
One poster in another thread made a comment to the effect of (para-phrased) "it's not a mechanical problem that you choose to farm all these different characters instead of focusing on one team at a time." I am guilty. 100% guilty, my completist mentality forces me to try and unlock all characters. I did not focus on ships as much as I should've, and that cost me the ability to farm zetas, the focal point of my problem.
Using my GM Yoda as an example, here is a G11 toon with Mk5 mods in all slots, but swgoh.gg informs me he is only at 76% of max power. No zetas.
Dev posts from other threads indicate that GW tables do not account for Zeta abilities as of yet when calculating power, teams and nodes.
Pretty sure the whole node problem can be traced back to my lack of Zeta abilities, as that is 6k power difference (Yoda should be around 22k power maxed and mine is at 16k).
As such, if I put my Yoda, Vader, Palpatine, CLS and R2 in a group (no zetas on any of them) and they pulled a mirror team into node 12, all of those toons would likely contain zetas and generate the difference I am seeing in power ratings.
All the strats discussed in these posts are likely valid. Using resistance could be the best team for GW. I never needed my resistance team for anything besides the mods challenge. I am going to work to get zeta abilities asap and I would wager my success in GW will return after I get a couple.
In the meantime - if the devs do roll out zeta considerations to GW Tables, it should bring the 20-25% gap in power back inline with folks that don't have zetas. On the other hand, they may not and force us to farm zetas to get back in the easy farm mode that other players are still enjoying.
Hope that helps someone from rage quitting or breaking their devices! :)