I’ve had similar from my other half. Assuming you’re making two, warming the cups and serving the second one to her, along with steaming the milk while the second shot is extracting is about as much as I’ve found possible to make it as hot as it can be.
Espresso and flat white are short drinks in a wide mouth cup so inevitably they’re just not going to stay hot for long at all. Not are they supposed to really.
Obviously an Americano with milk or something along those lines should be very hot and stay so for longer.
Failing that, serve it in a paper cup with a lid 😂.