As mentioned before, please create a diagnostic report and share this with my colleagues from support. Without that it will be total guesswork to why the devices are offline and unavailable.
Since all of your devices are going offline at the same time, this looks more like a complete failure somewhere in the Thread network rather than individual devices simply dropping off the mesh. But without that report, it’s very difficult to say what’s actually happening.
I also see a lot of IKEA stuff, have these been updated to the latest firmware version?
