As a Pro sub, do you use Kurt's Token Action Menu? We use it at our table and we have a character that frequently switches between bow and melee, so the ability to swap out the shield easily AND see when it was on/off was required. What I did was add a shield to the inventory but amend it to give no bonus to AC, so it just gave encumbrance (you could also unequip it of course). Then added a global AC mod called Shield with +2 mod. This then shows green when the player clicks the button to have it to hand, click it again to put it away. Player can do it, DM can do it if needed, but easy, comes from same menu we use for combat actions and visually obvious. Just another solution