Why This Works
The spritz is the most forgiving format in the bitter family, because carbonation and dilution soften the aperitivo into something you can drink for an hour. It is built for the aperitivo hour it is named after: low intensity, high refreshment, meant to open the appetite rather than overwhelm it. That gentleness is exactly why it survives losing the alcohol so gracefully.
The orange is not optional. Its oils on the surface and its sweetness in the glass are what round the aperitivo's bitterness into balance. Use a generous slice, and build the drink over plenty of ice so it stays cold and lively to the last sip.
The Alcohol-Free Swap
Alcohol-free aperitivos have come a long way, with genuine gentian and bitter-orange character. This is the easiest way to show one off.