I want to put up a lattice panel for privacy. What to attach it to?

I think a great way to get some privacy here is to approach it like a fence panel. Place stakes into the ground and attach your lattice to the stakes. This way you will not have to drill into the brick or fasten to the iron support.

If you dig in a 3X3 or 4X4 post by the wall it will make your installation more solid. Dig in a 2X4 for the other end of the lattice. Attach your lattice with screws. Be sure to dig in the posts at least one foot or more, as far as you can, to make it sturdy.

Hi there, you can always put a post in the ground to attach the panel too. Here's are some examples, you can build it so the lattice is standing up at its tallest or laying down.

You can put a frame around the panel(s) and attach chain links and S hooks, and hang it from the hooks like you already have at the top of your overhang.

If I understand your picture correctly you do not have the room to dig a post hole, because it would be on your neighbors space is that correct? Which is your space? The one with the toy car or the one with the table and chairs.?

is the skinny poles with points good to bahg in ground

For apartments with adjoining deck these planters work great, or you can make your own from a large planter and a piece of lattice..... https://www.wayfair.com/keyword.php?keyword=planter+with+a+trellis or check your garden center at the big box store.

Also you could get creative with a long piece of bamboo and some 2 litre plastic soda bottles in green to make your own temporary wall.... https://www.youtube.com/watch?v=YxKXO9pd-4E&t=30s You can even make a mini garden for salad and herbs.... https://www.youtube.com/watch?v=K9vN2eudWcQ&t=279s

dd🎆