const successNotification = window.createNotification({
    theme: "success"
});

successNotification({
    title: "Úspěch",
    message: "Úspěch"
});

const errorNotification = window.createNotification({
    theme: "error"
});

errorNotification({
    title: "Chyba",
    message: "Chyba"
});

Případně jenom:

window.createNotification({
    theme: "success"
})({
    title: "Úspěch",
    message: "Úspěch"
});

window.createNotification({
    theme: "error"
})({
    title: "Chyba",
    message: "Chyba"
});