[PaulK]

That looks ragged enough to make it difficult to repair in wood. You’d have to make the hole bigger just to square it off. It already appears like it’s got a bevel on three sides. Filling it in with a fiberglass/epoxy repair would be quicker & easier than wood. Maybe with a waxed piece of plywood on the inside to create a mould & support it until it kicks. A layer or two of ‘glass cloth/epoxy, then some epoxygoop with chopped fibers for strength, then another layer or two of ‘glass cloth/epoxy to tie it in with the outside of the hole. Sand it smooth on the outside and you’re ready to paint.