Now the hallway is done

so now I'm thinking of tackling the basement.
The people we bought the house from had problems with moisture in the basement, so we thought we would have to redo all the drainage. But when we dug in new water, we noticed that it was already done.
So what you can see in the basement is moisture damage from before.
But what I'm wondering is what to repair all the walls with. I saw that Ardex 828 would work for spackling everything.
Or what do you think, should I go for Ardex or something else?