I agree with you except for point 2. A well performing model should show such drastic changes wrt the seed value. Besides the huge amount of training data as we

I agree with you except for point 2. A well performing model should show such drastic changes wrt the seed value. Besides the huge amount of training data as well as test data should mitigate differences in data splitting. There would be difference but my hunch is it would be negligible. Of course as you said no one has tested this out so we can't say how the performance would change either way