I've been thinking it might be worthwhile to showcase that you can make GrapheneOS look beautiful or the same as stock Pixel UI. When I was considering switching from iPhone I had this misconception that it would look ugly or wouldn't look the same as Pixel UI, which is not the case at all. When I asked about it I wasn't given this clearcut answer that you can make GrapheneOS UI look the same or better than Pixel UI.

How much flexibility is there in changing appearance?

As an iPhone user, I really like what Oppo is doing with their ColorOS: https://www.oppo.com/nz/coloros16/