One tray does not have to mean everything goes in at the same moment. Potatoes need time to soften; cooked chickpeas mostly need warming and a little color.
Cut 400 g potatoes into small, even chunks. Toss with oil and a little salt, then roast at 210°C / 410°F for about 20 minutes. Add a sliced pepper and onion, stir, and continue roasting until the vegetables are nearly tender.
Add a drained tin of chickpeas for the final part of cooking. Turn everything carefully and finish when the potatoes are tender and the pepper has browned edges. A squeeze of lemon and chopped parsley bring the tray together.
This makes two meals with a spoonful of tahini dressing or plain plant yogurt. Keep the tray in a single reasonably loose layer. If your tray is small, use two: a deep pile of vegetables will steam even when the oven is hot.