Kajplats - my new nemesis?

I've used the old Trådfri bulbs since forever, and since 2023 in my current home. Some of the bulbs have said their final goodbyes, so they need replacement and I also wanted to make more rooms in my house Smart Bulbed. Went to IKEA, noticed there were no more Trådfri, only Kajplats. Thought "Oh well, it'll be fine." It is not fine!

They won't connect! I am using the IKEA Trådfri hub, and no outside apps or anything. No matter how many times I scan the QR-code, no matter how many times I turn the lights or my phone off and on, no matter which phones I try, it just keeps buffering on the final stage. My IKEA app does notice that the bulbs are there and prompt me to add them, but it never finishes.

I have gathered that there seems to be something about the 2,4 Hz network on my router, but I don't have access to it.

I don't know what to do, and I also don't know what I don't know, so troubleshooting this is a nightmare :( Help!