Hi Julian and welcome!

There have been balcony gardeners who have posted here in the past about the challenges of growing with a solid wall on the balcony. Seems most of the pictures of that arrangement have come from Californians and Canadians.

What you might want to consider is creating shelves that will raise smaller plants up towards the top of the wall to get the sun they need. Usually the sun reference is in terms of the foliage as the plant needs that to photosynthesize through the leaves. Sun at the base will warm the soil, so it's not necessarily deteremental unless it's blazing (and that can fry the roots depending on the pot size, color, type, and watering habit).

The wall can definitely help with growing shade-loving plants, although it will probably depend on which way the balcony faces, whether there are any trees, buildings, etc., around that can block it, and how the sun travels across the balcony (including going up over, with sun shining down on the area behind the wall, etc).

Anyway, some of these things you may not know yet until you move in and observe how and where the light hits and at that point, you can move the plants around or up higher to get the amount of sun they need.