Your question is: will the K1 be denied because of the prior K1 my partner had?
Answer: Most likely not but no one can tell you YES or NO either way because we are not the CO adjudicating the case.
The side note is: if it is denied you’ll have to go with the spousal. so, if you’re worried about denial GET MARRIED and then you got some extra (unwanted) advice on why spousal is better.
It seems like you’ve already made up your mind and are going with K1 even if you’re told this second K1 would be denied 100% so not sure why you asked the question.
Anyway, I’ve said all I can and don’t feel I can contribute further.
I truly wish you good luck, a speedy process with no issues and a seamless transition to the US. And SA is amazing I’m sad you have no desire to move to my country.