to subscribe all: open in browser the list > open dev console(F12) > execute next script and wait a bit:
// Select all <a> tags with class "general_btn subscribe" but not "toggled"
let elements = document.querySelectorAll('a.general_btn.subscribe:not(.toggled)');

// Function to click each element with a delay
function clickElementsWithDelay(elements, delay) {
elements.forEach((element, index) => {
setTimeout(() => {
element.click();
}, index * delay);
});
}

// Click each element with 100ms delay
clickElementsWithDelay(elements, 100);

Why is the "subscribe to all" button missing from this collection?