The literature is quite extensive that although standardized tests have substantial predictive power as to college performance, adding grades and other factors is substantially better. Eg https://news.uchicago.edu/story/test-scores-dont-stack-gpas-... and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6963451/
You assert without evidence that testing is unbiased. This is widely disputed. You will find some literature taking the opposite view, of course, but given that the debate rages among professional researchers, a plain assertion doesnt carry all that much weight.
http://m.portlandobserver.com/news/2020/jan/14/college-admis... https://files.eric.ed.gov/fulltext/ED537716.pdf
Cheating on college entrance exams is rampant in China and other countries. This is another downside of high stakes exams.
As far as a wholistic view, I think including attributes such as grit, leadership, and talent across many areas such as writing, the various arts and many other fields is useful.
