Where are you based? I just bought 25 from CPC without any issues. Delivered in two days. They aren't as cheap as they used to be, but I understand the reasons why, given how expensive RAM is. Yes, the zero is trickier, but the 2W is in stock on PiHut at the moment.
Thank you so much for the heads up! They're as 'rare as rocking horse ...' as an old teacher of mine would say. And I've needed one for a project for ages.
Unfortunately thanks to the EU's new tariff regime it would cost over 30eur to ship it here, but luckily I can smuggle one back from my next trip to the UK...
That said for 4 and 5s - I've not had a problem here (Finland) in literally getting them off the shelf of a local retailer (Partco) for the going rate anywhere else.