Modded Elden Ring talisman that makes you invulnerable: absolutely no sweat, almost trivial
Modded Elden Ring talisman that makes you invisible: a little tricky, you gotta get clever to find the right VFX id, but pretty doable
Modded Elden Ring talisman that gives infinite iframes: nearly impossible, maybe if you edit every animation for the player character, good luck lmao