reserving items in cart

Site URL: https://www.hubcityvintage.com/watches

On our online store, almost every product is different. People often compete for the same item.  We have done tests and have found that the item is not reserved on checkout.  Its race for our customers to put in credit card details.  Often times it seems like a customer has secured an item and finished the purchase process, only for it to say "cannot complete," or something like that, with no warning to the customer. Not only is it frustrating for our customers, its also very confusing. The website does nothing to explain that their payment won't process because the item has already been sold. Is there anyway for this to not be the case? I thought that once you hit checkout items where held. Can anyone help me with a solution?

I can't image there are any major commerce systems that would reserve a product just because a customer put something in the cart. It's just not workable.

I can't tell you how many times I've put something in a cart with the intent of buying down the road when I have more items to buy. Now imagine if several thousand others did as I did. The merchant wouldn't be able to sell anything because all the inventory would be reserved for people who may or may not actually buy!