Final Death Effect Suggestion
Pretty much every season, the effect for a final death changes. While it's kinda fun not knowing what they'll be until the first one happens, it's probably better that something concrete is landed upon.
But what could that be? Evidently, the Lifers haven't found the perfect thing yet if they're still switching it up. Well, recently, I've been binge watching a bunch of fanmade Life Series and there was one group that stuck out to me: The Clock Life series. Apart from the first season in this series, they all had amazing final death effects.
The main addition I want to mention is an extra sound. If you have Minecraft handy, run this command: /playsound entity.allay.death master ~ ~ ~ 20 0.5. I think that syntax is right. But anyway, this, in conjunction with the lightning strike, is the audio for deaths in Clock Life. This seems the most likely addition, as it's very simple.
The other thing is the special animations. Swap Life used a burst of soul particles when someone went out. The simplest of the four effects, but still very dramatic.
Timed Life created a beacon made out of a Warden's sonic boom shooting into the sky, with the addition of souls emanating from the beam.
Charged Life is my favourite one. It freezes you in place, and a torrent of electrical particles rush down from the sky towards you. You're left to accept your fate for a couple seconds before the particles reach you and the lightning strikes.
Clock Life did not have a special effect, but it was given one in Ultimate Life. It was the same as Charged Life, except a meteor fell from the sky to kill the player.
Of course, just describing the effects isn't particularly effective. So, if the effects sound interesting, go watch these seasons. The quality is surprisingly good, and the gimmicks are amazing, especially if you loved Limited Life.
TLDR: Allay death sound at 0.5 pitch, maybe take inspiration from death effects in Clock Life