The question reads like an XY problem, they describe DB functions for data structures so unless there's some specific reason they can't use a DB that's the right answer. A "spreadsheet for data structures" describes a relational database.

But they need rectangular structure. How do they work on tree structures, like OP has asked?

Relationships. You don't dump all your data in a single table. Take for instance the following sample JSON:

  "users": [
    {
      "id": 1,
      "name": "Alice",
      "email": "[email protected]",
      "favorites": {
        "games": [
          {
            "title": "The Witcher 3",
            "platforms": [
              {
                "name": "PC",
                "release_year": 2015,
                "rating": 9.8
              },
              {
                "name": "PS4",
                "release_year": 2015,
                "rating": 9.5
              }
            ],
            "genres": ["RPG", "Action"]
          },
          {
            "title": "Minecraft",
            "platforms": [
              {
                "name": "PC",
                "release_year": 2011,
                "rating": 9.2
              },
              {
                "name": "Xbox One",
                "release_year": 2014,
                "rating": 9.0
              }
            ],
            "genres": ["Sandbox", "Survival"]
          }
        ]
      }
    },
    {
      "id": 2,
      "name": "Bob",
      "email": "[email protected]",
      "favorites": {
        "games": [
          {
            "title": "Fortnite",
            "platforms": [
              {
                "name": "PC",
                "release_year": 2017,
                "rating": 8.6
              },
              {
                "name": "PS5",
                "release_year": 2020,
                "rating": 8.5
              }
            ],
            "genres": ["Battle Royale", "Action"]
          },
          {
            "title": "Rocket League",
            "platforms": [
              {
                "name": "PC",
                "release_year": 2015,
                "rating": 8.8
              },
              {
                "name": "Switch",
                "release_year": 2017,
                "rating": 8.9
              }
            ],
            "genres": ["Sports", "Action"]
          }
        ]
      }
    }
  ]
}

You'd structure that in SQL tables something like this:

I disagree with that framing, someone not buying your shit is not the same as you losing money. Inkscape saved millions for graphic designers, which is very different. Adobe was not entitled to that money, you can't lose something that was never yours.

Some local residents have not been onboard with the lack of car spaces at the new station.

If you need a car to reach the station it's questionable to claim you're local.

What's the end game for cancer?

There isn't one, it doesn't matter that the host dies eventually as long as they get to keep growing for now.

I leave on time, how is that an insult? I'd be much more insulted if someone asked me to work for them for free. That's what unpaid overtime is.

It's a little weirder than that.
https://lastplacecomics.com/lasso-man/

And some follow-up comics.
https://lastplacecomics.com/paint-bucket-man/
https://lastplacecomics.com/copy-and-paste/
https://lastplacecomics.com/lasso-man-4/

QR codes essentially just encode text, as long as you're using a sensible QR code reader and check any URLs before opening them there's minimal risk to scanning a QR code.

with extras like [..] no lockscreen ads

What the fuck? Why is that an extra not just the default? It's great that this product isn't riddled with ads, but that's like saying it's great a burger is not made of human shit; it's crazy that anyone would tolerate a shit-burger in the first place.

Maybe ads are normal in the e-reader space for some reason, but that's just insane to me.

You're not wrong, but the first words are literally "Just over a decade ago". It's not a news article, it's the story of the research in 2013 which revealed bitcoin isn't anonymous.

In place of cookies, Google has introduced a new set of tools that makes the Chrome browser itself keep tabs on what you’re doing online.

So instead of cookies which can be blocked or deleted relatively simply there's spyware baked directly into the browser. How is this an improvement for the user?

Public transport too. It really seems like every time a public service is privatised it goes to shit, almost as if for-profit motives aren't aligned to public interest.

That's an odd complaint. If they didn't ask for donations, donations would be a lower % of their income. How many donations do you need before you can ask for donations?