The principle being demonstrated here is persistence, and it exists on a spectrum. In a single Minecraft server your inventory is persistent, but across Minecraft servers only your account identity is persistent. In Valheim or Terarria both your account and your inventory is persistent across servers.

Right now the talking heads are trying to sell us a metaverse on the idea that one account could have a persistent inventory between Minecraft and Valheim and Terraria, but anyone who's ever played a game can tell you immediately that this makes no mechanical sense whatsoever (cross-game promotions are common, and welcome (e.g. an Aloy costume in Monster Hunter World for PS4 owners, or Nintendo Amiibo giving you random rewards in various games), but don't involve literally round-tripping your character between games of potentially wildly disparate genres), and anyone who's ever written a piece of software can tell you immediately that this would be an infeasible logistical nightmare to implement.