Your chain really breaks down with Nyriss, because she was on an extremely potent DS Nexus that was strong enough to make FOTJ Luke and Jaina have a tough fight against six relatively unimportant combatants. This means Surik's power would have been *heavily* gimped here, and Nyriss' amped, so we can't establish Nyriss > Surik since Nyriss experienced an insane amp from the planet. Even in this state, Surik was able to prevent the lightning from actually hitting her with a quick barrier defense, but was still forced back. We simply don't know how Nyriss does against Surik without the extremely potent amp from Dromund Kaas, but it definitely would have been more equal considering that Surik was able to form a quick barrier defense against lightning that could turn armoured guards into charred husks.
On top of that, Dooku's own lightning feats aren't really impressive.
Originally posted by HP_Legend
Now this would be great if you could actually scale Traya to The Exile which you can't because the latter killed her while on a Dark Side Nexus after depleting her Force Reserves while fighting through an army of Sith assasins which you actually made note of here. There is no way to scale any of Meetra's showings to Traya because they're not comparable in the slightest.
Traya scales off Surik because she's explicitly stated by an OOU source as being more powerful than the exile by the time they face each other in the Trayus academy core. That means Traya is more powerful in the Force than Surik, who's mentioned by Canderous as having a parity to redeemed Revan, who is > SF Malak and therefore also > Exar Kun if you follow that quote. Surik wins due to her superior combat skills, not power in the Force.
Although scaling is important, feats and combative ability also matter. Traya is > Dooku in combative feats and potential abilities during a fight, most notably teleporting and shatterpoint, both of which would throw an unprepped Dooku totally off-guard, imo. In terms of overall power, I'll reiterate that the Sith of the triumvirate, or rather the converted Jedi from the Mandalorian Wars are implied to be >/= to PT-era Jedi in terms of overall combative abilities, since they had to train heavily to face other force sensitives on a regular basis, and many had tonnes of experience in that area. It's also implied that Traya won her position as head of the Sith through her skill with the blade, no small feat against elite Dark Jedi and Sith who had killed well over ten Jedi in single combat.
I feel like that's all I need to address at this point. 🙂