Create your family chart in the app, print it for the fridge, then keep it current with taps or Siri. Kids keep using the page. Android follows Play Store readiness.
The paper stays. The parent phone keeps up.
At four, the chart is about repetition, not productivity. Toys in the bin, dirty clothes in the hamper, brushing teeth with help, helping set the table, feeding the dog with a parent nearby. Icons help, since the reading is still catching up. The win is that the chart exists at all, not that it is finished.
Three to five. More than that and a four-year-old quits looking at the chart. Pick the things you would already nag about, write them down, and let the chart do the nagging.
Stars are a record, not a currency. Use them to see what happened during the week. If your family pays for bigger extra jobs, keep that rule separate from ordinary family responsibilities.