Why don't all linear-gradient options for text work on IOS?

Question

css

Here is the code:

.button-inline-gradient {
    font-weight: bold;
    background: -webkit-linear-gradient(90deg, #fc2c90 0%, #ff521c 100%);
    background-image: -webkit-linear-gradient(90deg, #fc2c90 0%, #ff521c 100%);
    background-image: -webkit-gradient(
        linear,
        left top,
        right top,
        from(#fc2c90),
        to(#ff521c)
    );
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
}

Works in all browsers on Windows and Android. On ios in safari and chrome, the text is not displayed at all.
In other words, in iOS "-webkit-text-fill-color: transparent;" works, but "background" is not

For reference: lines with background-image added out of desperation, but they are unnecessary, yes