I am not familiar with the app Guru Maps, but I assume the routing engine works in such a way that access=private is not completely ignored, but only assigned such a large penalty that it is very unlikely that the path will be taken unless the detour becomes too large.

mapy.cz for example correctly shows that the end point is in an area with limited access (or takes the detour if you want to get to the other side): https://en.mapy.cz/zakladni?planovani-trasy&rc=9iwHLxIeyc0gAJ&rs=osm&rs=osm&ri=20588180&ri=20588180&mrp=%7B"c"%3A132%7D&xc=%5B%5D&x=15.4413110&y=47.0400076&z=18