A few points on preorders, especially for those in the UK/Europe:
Credit card charges: these can be misleading. There are no fixed rules as to how these things work and even two different transactions with the same card and supplier can be treated differently. A pending charge is usually a good sign, but they don’t always mean something is happening. I’ve had pending charges appear and disappear with preorders. Only when the charge moves from pending to confirmed does it mean your item is definitely on its way. I have had a pending charge for my Apple TV for a couple of days now and it is likely that this means it will be dispatched soon (a week before the stated date) but not certain.
Preparing to Dispatch: Recently Apple have been putting items to preparing for dispatch status very early. People were reporting this happening almost immediately after preordering with the Airtags and then they stayed at that status for nearly a week. I have seen items staying at preparing for dispatch for days a lot recently (ie iPhone 12). If your item has been showing this status for a few days this is not unusual and doesn’t in itself indicate that anything is wrong.
Will your item arrive tomorrow? I’ve seen a few comments saying that it is too late to arrive tomorrow as the status is still preparing for dispatch. In the UK (and I believe Europe) this is generally not the case. When I preorder items from Apple i usually get a dispatch notification during the afternoon or evening of the day before. The latest time that my item has moved to dispatched status was about 8pm the day before. Rarely does it happen before midday. There is still about 12 hours to go before I would say it is too late for delivery tomorrow. If items had been marked as dispatched my now that would have been unusual.
Will people on this thread be reading too much into things and panicking? Yes, of course, that is basically what these threads are. Every release lots of doom and gloom because of order status and credit card charges and then the vast majority of people get their items on time.
The great unknown this time is that so many people have estimated delivery dates so far after release date. I almost always get my order in time for release date delivery but this time I have 27 May for the Apple TV and 3 June for the iMac. Given comments here I expect most of us to receive these items earlier than those dates. I am hopeful that the Apple TV may arrive tomorrow (preparing for shipment and pending charge), but equally it may not arrive until nearer the estimated date. As there has been no movement at all on the iMac the chances of dispatch for tomorrow is remote but I’d day there is a good chance for next week.