A better source for what? It doesn't boil down to one metric or statistic.
I see you didn't actually read the link I pasted, especially not the section "Evaluating languages for projects". There's several possible ways you can compare (StackOverflow survey, JetBrains survey, GitHub PRs, StackOverflow trends, Google trends) but ultimately it comes down to what's a good fit for your project.
The claim being made in the original post and subsequent posts is that c++ is losing popularity. this claim is not true, and all evidence points to it gaining in popularity despite the HN echo chamber that it's too hard.
I still see you didn't read what I wrote. Please, just take a moment to read before firing off a comment.
I didn't make the claim that C++ is losing popularity, but I did mention some sources that do. These are marginal, not dramatic declines. Certainly not a terminal decline.
The original claim is "C++ is becoming a legacy language". This is clearly a claim about the trend of C++'s popularity over many years. You're trying to refute that claim with a single data point about one year, which isn't sufficient to refute a trend. For example, a single bad day in the stock market doesn't refute the claim "the stock market is trending up over the year". Moreover, your data point is probably just noise--a 4% swing when the error margins are closer to 50%. TIOBE is basically just guessing, and a guess isn't evidence.
FWIW, I've been a professional C++ programmer, and I like C++.
>You're trying to refute that claim with a single data point about one year, which isn't sufficient to refute a trend.
Below the list a graph showing the ratings over a 20 year period is provided. It shows C++ declining until about ~2017 but recently starting rising again.
https://blog.nindalf.com/posts/stop-citing-tiobe/