I think I would cover the roots with sphagnum moss, water less, stop fertilizing, put them in shade/dappled sun. They don't look that bad. Of course there are these spots. And the new leaves seem a tiny bit too pale, but not excessive. Not familiar with any fungus that does this, but we don't really have many azalea pests here in Europe (as we have no native azalea species). But if fungus is able to grow on the leaves, they must be too moist? Less moisture, more ventilation? If you know the actual fungus, you could try a fungicide. At this point, I think I wouldn't go for a broad spectrum fungicide (ie copper ions). The paleness of the new leaves could either get worse and turn into actual chlorosis, or just go away. So keep an eye out on that. That's always the main thing to look for when judging azalea health at this time of year; how much new leaves does it have? And how green are they?
It is easier to maintain health if kanuma completely covers all the roots/most of the nebari. If it is not a sunny warm low humidity day, you can let the kanuma dry out. The colour of dry kanuma is different from wet, so it is easy to see when it needs watering. when the surface kanuma starts turning pale/dry, then you kind of know that the core of the roots, where the fine roots are, are still moist. And then you can water again. Potentially, you could even wait half a day, then water. What you don't want is all your kanuma particles to be permanently dark/moist. Or the surface kanuma to be pale/dry while it is sitting in the sun unwatered for the rest of the day. If with the watering you have done recently, you have never seen the pale kanuma, you know you need to water less. But you want the kanuma to go dry on days where not a lot of water evaporates from the leaves. Then you can keep it nice and wet on those hot low humidity days.
If your climate is very continental though, you may not have those low stress days in summer. And if you cover your kanuma with sphangum, you may not be able to see the kanuma, and you are slightly changing the dynamics. If you add sphagnum, the sphagnum should never be dried out.
And when you repot this tree, I would try to get rid of the black much/moss in those upper roots. Personally, I don't like moss growing on top of azalea roots. But I am not 100% sure if they are beneficial or not. Now, you exposed all these roots. But in a normal situation, the moss could help keep the most vulnerable roots moist and cool during summer. But they could also act like a huge sponge, interfering with proper watering. Maybe they are a good thing to have in areas with very dry summers. I don't have a definite thought on this. But when moss starts growing, and often it eventually will, they really change the dynamics of watering and moisture in the top soil.
In Japan, all trees are displayed with moss. But my suspicion is that the day after the display, they immediately remove the moss. Not sure if I vaguely remember hearing this, or if I am just making this up. But besides moss, there seems to be algae growing as well? Definitely seems too wet.