There is nothing wrong with store-bought pie pastry. All the cooling and rolling is already done for you and that’s a lot of help. Just remember that everything in the pie should already be cooked and then you need a hot oven to cook the pastry to flaky perfection.
Put a lot of cheese on the vegetables right under the pastry. Remember the holes to help steam escape. Pie and gravy always work well with chips or go fancy with fresh salad and herbs.