The theme used is a pretty current version of Elevate, not Andromaps, and the map is also one of OpenAndroMaps, as surface is rendered.
But the symbols/text size shouldn't be reduced by zooming, and also aren't in all but one example - that's just an optical illusion. As everything around is enlarged it seems that they are smaller, but they aren't. In the first example it seems like the text size is reduced via a Locus setting (or some bug), because in the theme code the size is constant.