ANY universe? Oh my gosh just plonk me in the middle of the candy store why don't ya...

I'd love to go on a Citadel shopping date with Lily (and pobsibly Tali'Zorah too...) (Mass Effect)
Or do the Whole New World magic carpet sequence with Lily
Or travel with Odile and just explore and learn junk (In Stars in Time)
Or unlock my Bankai (Bleach)
Or learn the Oshi No Ko eye
Or learn extra dashes with Madeline (Celeste)
Or learn explosion magic from Megumin (Konosuba)
Or have a big pancake breakfast with Niko and gang (OneShot)
Or learn all the bending styles (Avatar)
Or go to Eorzea and pat loporrits... after downing twelve fantasias (Final Fantasy XIV)
Or get a chance to pilot literally any super cool agile mecha
Or talk about art with Josee (Josee and the Tiger and the Fish)
Or help Yato, delivery god, get a job (Noragami)
Or work on gadgets with Lucca (Chrono Trigger)
Or learn witchcraft from Elaina and/or Luna Nova Academy
Or try on Samus' power armor (Metroid)
Or be there to help Susie, Ralsei, Noelle and Kris (Deltarune)
Or go hug Felicia (Mice Tea)... and have some tea
Or go hug Sucrose (Genshin)
Or go hug Emilia, Ram, and/or Rem (Re:Zero)
Or go hug Ajisae (Watanare)
Or go hug March 7th, or Yukine Chris, or Chisato, or Takina, or Aya Fuwa, or Marika Sakakibara, or Heath, or Lily Blind, or Sora Honda, or Ayaka Sakurai, or Ritsuka Hara, or Kanade Kurokawa, or Elsa Dorothy, or Yvonne Smollett, or Hinako Yaotose, or Nagisa Ootsuki, or Mashiro Komiyama, or Mulan, or...

I guess for now I'd settle on Kingdom Hearts, and learn the secrets of my own heart! Learn to wield both the dark and the light for what I think is right! :D