Use the quiet morning
Start on foot while the shopping streets are still settling. Cross Sint Servaasbrug from Wyck, follow the river south and turn into Stadspark or the streets behind Onze-Lieve-Vrouweplein. This part of the day asks for no booking and makes the city easier to read.
If you are leaving by train, keep your bag and the station in the plan. Crossing the river twice is pleasant when you have time; it feels less so when it becomes a late sprint. Coffee is a better first commitment than a tightly timed attraction.
Shops are not a guarantee
Sunday is a regular shopping day, with many central shops opening around noon. Individual traders are free to close, and holidays change the pattern. Treat this as an opportunity to browse, not a promise that a particular shop will be open.
If Dominicanen is your reason for going, check its own hours. The same applies to a restaurant or museum. A Sunday plan built around one confirmed venue and an outdoor route is more robust than a shopping list of addresses.
Pick one afternoon interior
The Natural History Museum lists Sunday opening, as do several larger museums, but exhibitions and holiday hours vary. Choose by interest: fossils in the Jekerkwartier, art at Bonnefanten, or the former church at Dominicanen. One interior is enough for most short visits.
Book any guided underground visit separately. It is not an attraction to add casually after lunch because departure times and meeting points matter. If no booking fits, the walls and park give you a worthwhile afternoon for free.
Leave a soft landing
Finish near the bank of the river where you need to depart. Wyck has cafés on the station side; the old centre has more obvious squares for a final stop. Check the return service before sitting down, especially if you are crossing a border.
A Sunday in Maastricht is best when the route can absorb a closed door. Keep the walk, meal and departure fixed; let the shopping and second attraction be optional. That is a plan, not a compromise.