I’m a fan of outlines, myself. There’s no such thing as a correct answer here. Yellow paint, sparklies, circling white lines, glowing, pulsing, rainbow stickers, whatever. As long as it isn’t as odd as god of war where runes emphasize all wilderness climbing walls, my suspension of disbelief is unfazed. Took me a while to figure out that you can climb them. I just thought they were decorative for like 5 confusing minutes.