Same question, no luck. Filed FB9067349.
Elements in a List on macOS 11 that contain a TextField work as expected. Clicking on the field triggers item selection. Hovering a bit reveals the editable field.
However, List selection is obviated when adding a button or an element with a gesture, simultaneousGesture, or highPriorityGesture with or without masks or with a built-in or custom Primitive Button Style accepting only double tap gestures.
This results in poor UI for a macOS app where double tap in a list would be an expected behavior that differs from a single tap. Unfortunately, the only workaround seems to be adjust UI with a "go" marker to the side... or skip a SwiftUI implementation. Weirdly, adding a gesture to the list item background works... once, and then starts seizing up.