  We theoretically investigate the crystalline anisotropy of topological phase
transitions in phase-controlled planar Josephson junctions (JJs) subject to
spin-orbit coupling and in-plane magnetic fields. It is shown how topological
superconductivity (TS) is affected by the interplay between the magnetic field
and the orientation of the junction with respect to its crystallographic axes.
This interplay can be used to electrically tune between different symmetry
classes in a controlled fashion and thereby optimize the stability and
localization of Majorana bound states in planar Josephson junctions. Our
findings can be used as a guide for achieving the most favorable conditions
when engineering TS in planar JJs and can be particularly relevant for setups
containing non-collinear junctions which have been proposed for performing
braiding operations on multiple Majorana pairs.
