Linux

I have a solution to this I use. If asked I just tell people to use Kubuntu. You might pick a different distribution, I choose Kubuntu for a variety of reasons.

"What linux should I use?"

"Kubuntu".

No other options given or discussed.

It's my "official linux" even though I no longer use it personally.

Now you just have to do the same. Pick your own official linux that's going to be the only one you tell people to use in real life.

Maybe in a few years they'll decide to distro hop once they understand more, but right here and now they want one answer.

"There are 14 competing standards!"

"We should make a new one that has all the benefits of the others, and everyone can use that."

"There are now 15 competing standards!"

Rinse and repeat.

"To get around this, I would suggest basing the official Linux distribution on Debian but with a few queues from other distros"

"Now there are 15 competing standards"

If you buy a brand new computer, virtually all of them come with Windows or Mac pre installed. For the overwhelming majority of users, they are satisfied with either of these options, and can do everything that they want to do with a computer on these operating systems. The overwhelming majority of users aren't willing to go through the effort of mounting a Linux distro onto a USB, navigating through the BIOS to launch the OS' installer, partitioning their drive to avoid deleting all of their data accidentally, reinstalling and setting up all of their programs again, and learning how to use an entirely new operating system just because "Linux is free, FOSS, and gives you more freedom". The only times Linux has seen widespread adoption is when it comes bundled with specific hardware already, such as with the Steam Deck or Chromebooks