Too autistic for this. Why would it be unsettling? Mercury is much smaller than the sun. If it was suddenly bigger in proportion to the sun, then I'd be unsettled.
It doesn't exactly unsettle me, but pondering the mind-boggling scale of celestial bodies and the cosmos can certainly be... humbling, I guess?
I had a co-worker a while back who couldn't talk about the great scale of the universe cause he'd get freaked out. It didn't come up much, but when it did, he'd be like, "Please stop, it's stressing me out" so we'd change the subject.
There was a time people thought Mercury would have some "twilight" acreage that was always at habitable temperatures. Then we learned that, while yes it is tidally locked with the Sun, it is locked in a 3:2 resonance so it does rotate with respect to the sun, and everywhere gets both scorched and frozen to uninhabitability.
It's very hard to convey the size of the sun in a photo. On earth, it isn't bigger than the moon. I don't think I've ever seen, in a real photo, just how massive the sun is. I absolutely dwarfs a planet, which is kind of chilling. I've never seen a photo that shows anything further away from the camera than a planet AND that much bigger.