it ends after this generation.

Gen Z is 1994-2004. The premise of this meme is false, but to answer your question, it’s Generation Alpha, as the Romans when they ran out of letters in an order would then switch to the Greek alphabet.

Alphas are typically distinguished as having always had high quality tech, for instance a tablet.
Z’s are the generation that grew up before tech widely accessible to them as children, and don’t really have a memory of a world before 9/11.
Millennials were named prematurely, rarely are there Gen Y’s that were born around 2000.

What about "nice"