So. I figured something out today. But it's probably not something the devs wanted me to figure out. Everyone might already know this but it's a pet peeve of mine when I discover a big exploit in a game without reading it online.

I bet there's no way you're able to stop players from world hopping metal into a storage container, using the portal home, then world hopping to grab the iron, and coming back instantly, is there? Not without disallowing item transfer entirely, or despawning an entire stack of valuable metal any time a character logs out with it accidentally lol.

So you're just punishing players who don't think of it at this point, then? Making them slog back. A twenty minute walk, or even worse in a boat. As if immersion is that important: You have an enemy called "Deathsquito" in your Norse Mythology game, immersion got left behind at the station.

It's a bad mechanic that is literally only there to waste 20+ minutes of your player's time with a boring task of doing nothing but holding W. This is not a factory game, and there is no automatic logistics gameplay here; everything is intensive on the player's actions. This mechanic is literally only there to pad the gameplay and waste the player's time and you know it. Take it out and wake up to yourselves.

Alternative solutions for your silly portal metal ban if you care that much. These are all bad ideas that are designed to screw the player over, but none are as bad as the current implementation:
Make portals cost more materials in general and remove the metal ban
Make portals a more late game unlock and remove the metal ban
Keep your hilarious metal ban good mechanic gr8 work and let me pay per metal (based on tier) to teleport it.
Have helpful bird frend Hugin tell the player they can log out, stash the metal in another world, portal back, log back in to instant metal, since that is the dominant strategy.
Remove the metal ban and replace it with - nothing at all :D