I think I’ve heard both Kent in sculpting and JL texture painting, saying that you shouldn’t spend too much time in orthographic, for the same reason you say, it can distort things, because it flattens the depth. I guess in perspective if you have a wide lens it can also distort things. I would say though that being in orthographic while sculpting is worst than in texture painting. The brush size would be cool if it adapted to the zoom, there might be an addon, try searching in the Blender Market. But in the end, I guess being mindful of your stroke and zoom just becomes second nature the more you texture paint. Perhaps other software’s have tools that adjust the brush size to your zoom. I might google that.
