A spherical shape with a complete coating of photovoltaic film (and possibly a second transparent outer shell to retain heat longer after sunset, or additional layers preventing helium or hydrogen leaks) would almost totally eliminate the need to orient the balloon towards the sun, while the wind would allow the use of the Magnus effect for a yo-yo mode.
A diametrical (and vertical) motorized belt would ensure the rotation.
See also a spherical airchip and its device ensuring rotation on
See also the publication below about rotating sphere, and the figure 1 to start, then the figure 5.
The lift coefficient Cl looks to be far lower (about 0.3 or 0.4 among other close values, according to considered studies, Reynolds numbers, and spin ratio of about 0.5 to 1) than that of a cylindrically-shaped balloon (which perhaps remains more interesting, even at a low aspect ratio to favor an almost equal sun exposure at different angles). The drag coefficient Cd is significantly higher than the lift coefficient Cl.