Creating areas of different ph in the same garden

The soils in our region are acidic and you can grow azaleas and rhododendrons here. But our soil is fill (rubbish out of building places and soil asphalt etc.) and the ph is between 7 and 8. My veggies grow nicely, in something i adapted from huegelbeets.
I guess that the ph will change over time and intensive gardening, mulching etc and will be more like the natural soil.
I want to grow all sorts of plants and roughly the Mediterranean want more alkaline soil while berries especially blueberries want more acidic soil.

My guess, and I want to know if I'm guessing right, is that if I create a hill, then at the top the soil remains more as it is (ph 7- and at the bottom it becomes more acidic.

What mulches make the soil more acidic? And the shop bought powder (I think it is sulphur) is it OK or does it damage the soil live?

How far would you separate beds with more acidic and more limey soil? I.e. vegetable beds right beside blueberry beds?

Compost or organic matter in general leads to a soil that is mildly acidic and good for most types of plants. Some types (pine needles, peat) are more acidic.

If you are trying to have raised beds with different pH, they can be pretty much next to each other. If the beds you want to vary are flat, then drainage patterns need to be taken into account to a degree.

If your soil is fill, it may not naturally convert to acid soil, or it may take a long time. The natural acid soils you describe got that way through the parent material (starting block for soil) which many be different for the fill you got. Then it probably was driven even more acidic by vegetation and biological processes (pine needles, peat, etc).

One thing that standard soil science over-relies on is the soil reaction or pH of liquid from the soil. They take what amounts to a huge average over time and space. Standard ag advice is to apply finely ground limestone to raise soil pH. But larger chunks of limestone will create micro-zones of higher pH around the particle even when the overall reaction of the soil is more acidic, and this effect lasts much longer.  If the roots are around these alkaline microzones and around other acidic microzones, the plant can draw nutrients from both types of environments at the same time!

Sulfur can damage the soil, depending on the amounts used and how fine the particles are - smaller particles act quicker due to high surface area and more reactivity. Sulfur is converted to sulfuric acid. In smaller amounts, it won't kill the soil but it will change it (which is the goal). In larger amounts, it will have more serious effects.

Thanks for the answer!
I am digging in tons of organic matter. In A huegelbeet fashion, however  I don't hill up everywhere. Your conclusion is that the ph itself is not that important. And that I should not use sulphur. I can rake up leaves and put them on the beds. At the moment we have heavy rain but that can change to drought each month.

caution, runoff from an alkaline hill going down onto acidic soil will make the soil downstream alkaline, and will kill your blueberries.

I keep my alkaline and acidic plants separated by plant that will tolerate both types of soil

If a plant like blueberry doesnt have ideal PH what will happen to it? Will it die or just not fruit/grow as well?

if there is alkalinity it could kill it but it definatly won't do well