Glad you like the plugin :) - It is already possible to store items outside of the player's inventory, it just isn't enabled by default. You can enable it in the config.yml file, just change the "itemStorage" "enable" option to "true". This will give players the option to store items outside their inventory. If you want, you can also change the "stockLocations" option to remove or change the order of where the plugin looks for the items.

Glad it is what you were looking for :) - I'm going to make the area that shows the ores, as quick selections for the price, customisable (and with that also add copper and netherite as defaults). I hope to release an update with this in a few days. Thank you for your suggestion.