Behold! Following zathurarc file makes zathura keybindings at least as comfortable as those of MuPDF, while also eliminating the need to press Shift altogether. Altogether!

map d scroll half-down
map u scroll half-up
map . navigate next
map , navigate previous
map h adjust_window best-fit
map w adjust_window width
map s scroll page-top
map a scroll page-bottom