If you’re near Tottenham Court Road, the Elizabeth line provides a direct, modern train to Heathrow

https://www.scribd.com/document/1074929924/National-Rail-to-Heathrow-Routes-Transfers-and-Tickets-Explained-232993

If you’re near Tottenham Court Road, the Elizabeth line provides a direct, modern train to Heathrow, often faster than the Piccadilly line.