KaiOS has a known launcher bug. Go to Settings > Device > Storage > App Manager. You will likely see the apps are still installed but hidden. Reinstall the launcher via the KaiStore.
The phone must be connected to or have a stable 4G data connection to check. Latest Version Status How to force update your Nokia 800 Tough to KaiOS 2.5.2.2
This is usually a network profile issue. Go to Settings > Network & Connectivity > Mobile Network > Access Point Names > Reset to Default. Then restart.
A: No. It runs KaiOS, not Android. It will never receive Android 12 or higher.
October 2021 updates ( 30.00.17.05 ) prevent rooting on the device, according to BananaHackers . If you want to know more, I can help you with: How to check your current build number Steps to troubleshoot "Update Failed" errors How to factory reset if your update is causing issues