If you want to mod, please be aware that the game officialy does not support mods. The risk of playing the game with mods lies entirely on you.

That out of the way, I would highly recommend installing the mod manager "ThunderStore" to manage all your mod needs. It can automatically update mods, en- or disable, configure, and uninstall individual mods for you and much more.

It also has a convenient mod browser with over 1500 mods listed directly in the app, and you can download all of them.

AFAIK there is multiple mods available that will allow you to move metal through portals. I can't remember the exact name, but I would just search for "portal" in ThunderStore.