Android runs an only slightly modified Linux kernel, and yet the OS requires much less from the user than e.g. Windows or MacOS.
Chromebooks run a bog-standard Linux kernel and the target audience is kids.
My car’s entertainment system runs a standard Linux kernel, and the UX is so cut down that PC expertise really doesn’t matter when using it.
MacOS and iOS, two systems known for their ease of use, both stem from BSD, which comes from Unix.
The kernel has nothing to do with this.
In fact, the only mainstream kernel used in user-facing operating systems that doesn’t “come from Unix” is Windows. Everything else is derived either from Linux or BSD, which both are derived from Unix.
There isn’t even a mainstream phone OS anymore that doesn’t “come from Unix”.
Number 3 happens all the time to me when using VSCode with Copilot as autocomplete. Copilot sometimes works, sometimes doesn’t. Also happens a lot when using Pycharm with Python. Sometimes it’s great at autocompleting, sometimes it completely gets lost and has no idea what my Python script is doing.
Number 5 also happens a lot on VSCode + Platformio. It also frequently happens on Intellij IDEA for me, but mostly when I am concurrently running build or test while writing. My crappy work laptop suffers from Windows 11 related performance issues, and when there’s not enough performance available, underlines do get wonky quite frequently.