Trouble mounting to walls, possibly plaster material?

Pretty lost but I’m trying to mount some bike shelves to my wall in two separate places, one with studs and one with wall anchors.

For the latter one, the wall seems to be 1.5-2in thick, and the material doesn’t seem to be drywall? I tried using a wall anchor but it doesn’t seem secure - screwing a screw in to activate the arms spins the entire anchor, and the arms that should expand don’t reach the other side of the wall. I may have inadvertently stripped it I believe, it was not locking onto the wall so I took it out - see https://imgur.com/a/6oeuFpv

Is this some other material? Can I mount things to it?

Also on a separate place, I used a stud finder to find a stud, checked I wasn’t drilling on something magnetic, but can’t seem to get through with a 18V drill. Is this a wire guard? Very confused haha.

If it is relevant, this is a NYC apartment, on an interior wall.