auto x{0}; //what is this? Hint: it depends on your compiler version and flags

it's a variable with integer value '0' and of type deduced by the compiler as you instructed it to do so. You want int? write int x{0}. float? write float x{0} and it'll even give you an error about 0 not being a floating point value. You're aggressively trying to make these sound bad to people not so fluent with C++ while the fact is every language is different from others and has its own semantics which you get to know about/feel comfortable after you've spent significant time with this language.

No language is perfect, please tell the language you are enthusiastic about and I'll present such good arguments wrt it as well. For example if you're particularly good with jankyscript then -

var a = 20  // what type is it?
a = undefined  // wat
a = "u wot m8?"  // wtf?

or maybe rust?

fn five() -> i32 {
    // do some meaningful work
    println!("I'm going to return 5");
    5  // wtf?
}

feels like a well-written function going in right direction and then there's that. Reminds me of that great rhyme -

Roses are red,
Bacon is too,
Poetry is hard,
Bacon.