You will be oblivious to the detail that the SNP fought (if you can call it that) their campaign entirely on keeping Reform out, and by characterising Labour of incapable of winning. There was not a single mention of independence, and that very probably wasn't a cack-handed oversight.
Many pro-indpendence Scots are angry at, and abandoning the SNP because they have become so timid about what is their single reason for existing. The voting stats from Hamilton are being broadly interpreted as a consequence of former SNP voters staying home.