Awtrix Light Countdown App with Node-RED. Paste code to a function node and customize the schedule on line 6 to your liking. Node will execute on any incoming message.

index.js

const prefix = "awtrix1";
const appName = "countdown";
const now = new Date();
const today = new Date(now.getFullYear(), now.getMonth(), now.getDate());

const schedule = [
  {
    date: { day: 1, month: 1 },
    text: "First of January every year",
    icon: "14004",
  },
  {
    date: { day: 1, month: 2, year: 2024 },
    text: "First of January at a given year",
    icon: "14004",
  },
];

function createNextDate({ day, month, year }, today) {
  if (day && month && year) {
    return new Date(year, month - 1, day);
  } else if (day && month) {
    if (
      month < today.getMonth() + 1 ||
      (day < today.getDate() && month <= today.getMonth() + 1)
    ) {
      return new Date(today.getFullYear() + 1, month - 1, day); // Project date to next year
    }
    return new Date(today.getFullYear(), month - 1, day);
  }

  return undefined; // Skip unknown date structure
}

function findNext(schedule, today) {
  return schedule
    .map((s) => [createNextDate(s.date, today), s])
    .sort(([a], [b]) => a - b)
    .find(([date]) => {
      return date && today <= date;
    });
}

const next = findNext(schedule, today);

if (next) {
  const [date, schedule] = next;
  const daysUntil = Math.ceil((date - today) / 1000 / 60 / 60 / 24);
  const hoursUntil = Math.ceil((date - today) / 1000 / 60 / 60);

  const until =
    hoursUntil === 0
      ? `Heute`
      : hoursUntil < 24
      ? `${hoursUntil} Stunden`
      : `${daysUntil} Tage`;

  return {
    topic: `${prefix}/custom/${appName}`,
    payload: JSON.stringify({
      text: `${schedule.text}: ${until}`,
      icon: schedule.icon,
      rainbow: next.rainbow ?? false,
    }),
  };
}