Canvas doesn't have a "unsubscribe from 63 email notifications", so you have to manually click each one. This does it for you

kill-canvas-notifications.js

async function wait(ms) { return new Promise((resolve) => setTimeout(resolve, ms));}
for (const svgName of Array.from(document.querySelectorAll('[name=IconCalendarMonth],[name=IconAlerts],[name=IconCalendarDay]'))) {
    svgName.parentElement.click();
    await wait(100);
    document.evaluate('//span[text()="Notifications off"][not(ancestor::*[@aria-hidden="true"])]', document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue.click()
    await wait(100);
}