As I understand the Parliamentary system, citizens have only an indirect say in who will be Prime Minister or in this case First Minister. They elect representatives, who on a party-line vote elect one of their members to be PM.
To put it in American terms, we’d be only a vote or two from having Hakeem Jeffries as our PM
Well, not really. He was elected head of the party by less than a majority (48%) of ~50k party members who voted, out of ~72k eligible to vote.
What many of those 96% whites did was to give that party's candidates a substantial majority of Scottish seats in the UK House of Commons, and almost a majority in the Scottish Parliament.