How can we improve the transport barrier of metals ?

Saw this post about how pain stacking It is to travel multiple 30min voyages though the sea just to transport metals, maybe we could change that:

-Boss trophies should not be possible to be transported by portal. Making you go back by boat after his defeat. That would make the experience of travelling more enjoyable

-Once the trophie actived, something happens to the portals, could be:

New portal recipe, by crafting a new portal (entrance and destination) with idk with plus 15 metals of the biome of the Boss defeated, you can transport that metal and below metals in those 2 portals, as said in the post above, a misture of the two ideias

That would make players that are in the endgame actually be more affordable to decorate their houses with itens that need cooper or iron. I have 300 hours in valheim, and my house has like, 2-3 iron chest… It doesnt make sense i travel 1 hour by boat just to craft some more… Those kind of problems…