Zavala never learned solar because the sun breakers hated him

Lol Facts though: Sunbreakers do not control the use of Solar energy among Titans, only the Burning Forge. Solar energy was used by Titans and Titan-like Risen before the Sunbreakers and the Burning Forge existed, and can still be used by Titans that aren’t affiliated with the Sunbreakers in any way. Saint-14 and the Iron Lords are our primary examples of this. We haven’t seen Zavala use Solar energy, and that is either because he rarely uses it, he can’t use it, or we just haven’t been shown that he can.