[B]How to use[/B]: Straightforward game plan. Just play well. Scout via Ting-Lu and Imposter and start finding some openings with Eternatus or Ghostceus. Cover most of the physical attackers defensively—especially Ghostceus since it interacts so little both defensively and offensively with the type chart. Etern is cool 'cause even if you don't even Tera, it punishes people who send in their Zacian thinking they'll KO it from full-ish with HR. Especially at +2. Zacian-C is a cool midgame breaker. Toxic + taking hazard chip wears down Dondozo pretty easily (Salt Cure also probably works here if you want more immediate chip, but Fireceus becomes more annoying, so I don't love it). Kiiiiiiiiinda have to out-finesse Imposter if it comes in on Don or Ting, but I had little to no problems doing that. Straight-up dogwalks most fat/stall builds.
[B]Weaknesses[/B]: GTactics Don if you don't opt for Tera Flying on Eternatus. Fuck that mon. Mostly went Tera Steel when I laddered, and it obliterated most of the team; only reason I still won was cause for some strange reason my opponent closed their eyes and clicked a button missing their game-winning play when my paralysed Ghostceus was the last mon standing and was well within KO range of their last Headlong Rush lmao.
-ate Boomburst anything can be an issue since nothing reliably switches in on it. Especially random Aerilates with Specs or Metronome. Terastallize Poison Ting-Lu immediately to handle Pixiburst Fairyceus, Flutter, and Iron V. If/when PH gets banned, you can easily go Eviolite > T-Orb on Imposter to further ease this MU.
QD Miraidon of any breed. Struggled a lot vs. these. A well-played Tera Dragon Specs can also be a huge nuisance.
PH Fairyceus with Steel/Fire Tera can also be a nuisance. Will hopefully no longer being an issue after the current suspect. If it sticks around, you can opt for Tera Ground on the Don.
[B]Effectiveness[/B]: I'm very, very terrible at saving replays, so I unfortunately don't have any. All I really have is 25-0 on first try on PH suspect with minimal effort aside from Onyx. Even though I was just shy of 1500s ELO by the time I finished, I believe the GXE was only surpassed by the top 2 in rank at the time, CHISIRYO and Quantum Tesseract.