That’s strange. As far as I can tell from any web searches, every version Windows still defaults to storing local time to the hardware clock and there are no reports of that changing with an update, nor is there any exposed setting control to configure this behavior outside of regedit. If you’re curious enough, you can check the current setting in the registry at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation. Windows maintains the current time as UTC if and only if the RealTimeIsUniversal key is present and nonzero.

I expect it’s more likely some other issue would make the BIOS display an hour that’s inconsistent with your local timezone. For example, maybe a bug in the BIOS, maybe a timezone offset setting within the BIOS, or maybe a dead clock battery.

Unix time is far less universal in computing than you might hope. A few exceptions I’m aware of:

• Most real-time clock hardware stores datetime as separate binary-coded decimal fields representing months, days, hours, minutes, and seconds as one byte each, and often the year too (resulting in a year 2100 limit).
• Python’s datetime, WIN32’s SYSTEMTIME, Java’s LocalDateTime, and MySQL’s DATETIME similarly have separate attributes for year, month, day, etc.
• NTFS stores a 64-bit number representing time elapsed since the year 1601 in 100-nanosecond resolution for things like file creation time.
• NTP uses an epoch of midnight 1900-01-01 with unsigned seconds elapsed and an unusual base-2 fractional part
• GPS uses an epoch of midnight 1980-01-06 with a week number and time within the week as separate values.

Converting between time formats is a common source of bugs and each one will overflow in different ways. A time value might overflow in the year 2036, 2038, 2070, 2100, 2156, or 9999.

Also, Unix time is often managed with a separate nanoseconds component for increased resolution. Like in C struct timespec, modern *nix filesystems like ext4/xfs/btrfs/zfs, etc.

as soon as the BIOS loaded and showed the time, it was “wrong” because it was in UTC

Because you don’t use Windows. Windows by default stores local time, not UTC, to the RTC. This behavior can be overriden with a registry tweak. Some Linux distro installer disks (at least Ubuntu and Fedora, maybe others) will try to detect if your system has an existing Windows install and mimicks this behavior if one exists (equivalent to timedatectl set-local-rtc 1) and otherwise defaults to storing UTC, which is the more sane choice.

Storing localtime on a computer that has more than one bootable OS becomes a particularly noticable problem in regions that observe DST, because each OS will try to change the RTC by one hour on its first boot after the time change.

The main reason people use Fandom in the first place is the free hosting. Whether you use MediaWiki or any other wiki software, paying for the server resources to host your own instance and taking the time to manage it is still a tall hurdle for many communities. There already are plenty of MediaWiki instances for specific interests that aren’t affected by Fandom’s problems.

Even so, federation tends to foster a culture of more self-hosting and less centralization, encouraging more people who have the means to host to do so, though I’m not sure how applicable that effect would be to wikis.