When I updated it, all the items in the inventory of the realm server I was using disappeared

I updated Minecraft this time and went into the movie server where it was an event and found that the inventory of the characters on the realm server that I kept playing was all gone

I downloaded and opened the map that I backed up before because it was an error, deleted it as a ㅔ, and re-installed it, but my character's item didn't come back

I was in a safe building on the realm server and didn't die. I kept the game on in the background and deleted it continuously. But all the items that should have been stored on the server disappeared. I'd appreciate it if you could solve it quickly