The Texas Revolution was not predominantly about slavery, although slavery was a genuinely held belief of many of the Anglo colonists in the area. This question has been answered satisfactorily a few times before, so I hope you don't mind if I link you to previous answers:

this one by yours truly covers the long and complex Mexican political narratives leading Texas, among several other Mexican states, to revolt

this one by, u/AlotOfReading , discusses the competing schools of thought and why it's important to imagine the situation in a Mexican political context rather than being considered an Americanized historical extension of the Civil War. They also reaffirm the central point of considering the Mexican narrative and offer a brief sum of the ideological drive and implications behind the revolution.