I'm trying to fill this hole to make a bowl out of this model. I tried patching it the hard way by taking a mesh plane and slowly transforming it to make the shape I need but I'm sure there's a faster way to do it right?
Assuming its perfectly round, set your 3D Cursor to the centre of the bowl, select all the vertices of the bowl, shift-d do duplicate and right-click to dump them in the same place. Set snapping to Vertex, Active and make sure a vertex on the corner of the V cutout is selected last (to make it active)
Set your transform origin to 3D Cursor
Then rotate the new vertices around the 3D Cursor snapping to a verts that puts them in the right place.
Select all and merge by distance.
If your bowl is not exactly as mine you might have some small clean up left to do but this will get the bulk of it done very easily. :)