If you're still undecided, I'd suggest giving yourself the space to treat this as research, not urgency. Clarity comes when panic recedes.
In terms of method, most people looking for something quick and relatively painless focus on SN. It's one of the few accessible options with a decent amount of documented guidance, especially through the PPH and recent peer shared protocols. It's not "peaceful" in the Hollywood sense, but compared to many methods, it's fast and doesn't require high pain tolerance.
That said, prep is everything. Without antiemetics, timing, and correct dosage, SN carries a serious risk of survival with complications. It's not something to half guess or improvise. If you go that route, read everything. Protocols exist not to make death attractive, but to reduce harm if someone has already made their decision.
No method is perfect. And no method is pain free in every case. But some are significantly less violent or medically risky than others if they fail.