I agree that once the player picks their item, they should be teleported back to their position, or at least away from the item picking zone, so that they can still move around and interact with other players, but aren't in the way of the players who are choosing their item to pickup.
Also I think 1 player at a time should be picking, so that the player gets their item, and then the next player is released...and while some enjoy the chaos involved with the current frantic setup, I find it pointless competitively! In comparison to just letting players pickup their items 1 by 1 to avoid non-competitive behaviors that would be disqualification in some cases during a competition.
Teamfight Tactics doesn't have to be serious as some of the other modeas in League, but it shouldn't be ridiculous either, because I don't play League of Legends because it's not competitive and does not make sense...I play League because it makes sense, and it is fairly competitive strategically, with a wise or otherwise brilliant overall gameplay mechanics, that can keep it interesting for a while. At least up until they may really disappoint their players to a point of quitting the game altogether for a long time, if not forever, and I can say right now there are popular games like Destiny 2 that I will never play. Perhaps if they do Destiny 3 I will give them another chance, but when I stop forever, that means your chances of me coming back are likely only from major improvements, with word of mouth as well to convince otherwise, or it remains literally forever...not that 1 person counts as much, but it adds up when so much disappoints. I have no object against Riot's League of Legends, but if it disappoints in absurd ways, whether it matters to them or not, I can forget about League personally at that point, because a company that cares about their supporters, respects their supporters at least reasonably.