A couple of potted trees would be nice. I think there are redbud, cherry, and Japanese maple that do well in partial sun. I have some cypress that are narrow and will only get about 10' tall. Something like that could make a wall feel more natural.

How long would you say you've got light? 3 hours maybe? Less? Are you looking for food to grow? Herbs? Flowers?

Change the soil? Try a cactus mix

I’ve had success with my ZZ plant in a limited sun situation. Something waxy could be easy and aesthetic. Also see if you can find any local plants for free or cheap on marketplace sites. Get some nice pots and something to set them on as well. Good luck and let us know how it goes!

succelents, if it gets alot of sunlight.

@YetiBeets what are you looking to do there?

A wall of ivy would be nice. Maybe make some planters that straddle the wall. If you need to "bribe" your wall neighbor there you could offer to have some hang over on their side to if they're interested.

Remove all the tiles

It looks like the neighbour's bamboo is thriving. That would let you cover the walls in greenery fairly quickly.

I'm not familiar with Sydney's climate but in Europe I'd recommend shade-loving plants like Ivy and Vinca, possibly some Ferns. You might be able to get away with something a bit more exotic though.

If it's warm over night you could consider keeping some house plants outside - at least during the summer. These typically cope much better with the low light conditions indoors. For example Pothos, Monstera, or Spider plants.

You could plant some Ivy's to cover the walls