(Upvoted since your comment was turning gray. It's a legitimate concern, I think.)

I think the story here is that they were overwhelmed with a high demand during the past "WFH and improve your home year" all while their production and shipment capacity was being more or less randomly reduced (separately in each country) with very little warning.

Stock sync issues? I used to think they had bugs there until I realized they're constrained in two aspects that are both unusually tight at the moment:

a) forecasted availability of products in your particular shipment center

b) forecasted availability of home delivery capacity in your particular region

Note that the two will have to match up for the same week at least (maybe less), or there'll be a pileup. In a normal year this isn't really a problem, there's some slack...

The strategy I eventually landed on was to give up trying to bundle everything into one neat order to save a little money. I've been ordering large/heavy stuff (like sofas/beds) for home delivery in separate deliveries, as soon as I've been able to decide on something. Smaller things I've been picking up outside their nearby store. If I didn't live near an IKEA, I'd order the smaller items by postal/package delivery.

“Large company employing thousands of autonomous people can only do one thing at a time.”

IKEA’s webshop is just a bad frontend for their stores. If you’re unlucky you add items to your cart that you would (according to their check out) have to drive 500 km to pick up. Probably a result of the stores themselves being the warehouse.

Most stores ship your order within 2 days. With IKEA your’re probably going to wait a week for them to handle the order and hopefully ship it.