I’ve read this a few times and it doesn’t seem right. Did WaniKani translate this correctly?
彼女は、美しく、尚且つ頭も良いが、性格は悪い。
She’s beautiful, smart, and yet she has a terrible personality.
I think it should be:
“She’s beautiful and yet smart, but has a terrible personality.”
I think the implied meaning is that it’s surprising that she’s both beautiful and smart hence the “and yet.” However, despite those good things she unfortunately has a bad personality. In the WK translation, “and yet” seems to be imply it’s surprising that this person has a bad personality and the “が” seems to be forgotten.