While watching LustKR’s stream last night, I could have sworn that I saw him transfer all of his gems from his character inventory to his roster storage all at once. When I need to transfer gems so another character can use them, I have to do it one-by-one. Is that a QoL thing only in KR? He is the only person I ever saw do that.
If you want a reference, go look at his Twitch VOD from last night and look around 2:49:38 seconds.
You can do it, to fully unequip you gems from your char, pres P → gems and change preset. Now all your gems are in your inventory, and if you change your gems preset back to the Preste 1 you will fully equip your gems. Now open your roster inventory and press the little leaf icon you have on the top right of your roster inventory window and you will move all your gems but also your unbound honing mats you have in your normal inventory