Baby showers are an old tradition in the US
They're not tacky or rude or attention seeking, and they're not bad luck.
They started as a way for the women of a frontier community to band together and welcome a new baby with practical items every baby needs - blankets, clothes, cradle, etc.
As time wore on and consumer goods became widely available, there were more shower gifts to choose from, and in order to prevent duplication and the bother of returning unwanted items, gift lists became a thing.
As with wedding gift lists, they tend to be handy and very practical and in the US a list usually includes items at all price points and also the choice to just send money. One of my penniless student DDs sent a cousin of hers a very inexpensive kitchen timer from her gift list for her wedding. It was paid for online and delivered along with a gift card.
As with many perfectly nice, practical American traditions, crossing the Atlantic eastbound seems to have resulted in many of the civilised and practical elements being lost overboard or misinterpreted - the wide price range that is common in American lists has not happened here, and the registry itself is being sniffed at for no good reason really except that it is considered rude or uncouth or grabby.
It's none of the above. It's time to drop the conceit that a gift is an optional extra and the pleasure of your presence is all that's needed. A shower is an occasion designed specifically to give items that are needed, and two or more guests clubbing together to get a more expensive item isn't at all untoward. Again, it's a matter of practicality.
Gift registries are practical, and if guests want to get someone something they really want, then a registry is the way to go. If guests want to wing it that's fine too, but maybe include a gift receipt sith your surprise gift, and ask yourself why you would feel OK with the waste of resources and impact on the environment your 'principled' stance involves, to say nothing of your time and the time it will take the recipient to return an unwanted item.