Aha, there are two types of links under “Your SimpleX contact address”: one time and reusable. This is my reusable contact address:

https://simplex.chat/contact#/?v=1-2&smp=smp%3A%2F%2FSkIkI6EPd2D63F4xFKfHk7I1UGZVNn6k1QWZ5rcyr6w%3D%40smp9.simplex.im%2Fjp5jfPL3sA4m7KFtmft-sj8SRXsPSi1L%23%2F%3Fv%3D1-2%26dh%3DMCowBQYDK2VuAyEAzkTkA98fck5jjKUe2Gg7p22iyLGf7a1g4MqYg6hSbGY%253D%26srv%3Djssqzccmrcws6bhmn77vgmhfjmhwlyr3u7puw4erkyoosywgl67slqqd.onion