I am concerned that there were many things not said and there are many discrepancies between what the parents report and what Sydney says on the internet. And if you look at Sydney's postings on the internet, her struggles go back several years.
The initial article in the News and Observer
https://www.newsobserver.com/news/local/article246239320.html seems to be about the only article that seems to not have some sort of PR spin to it. In it, her uncle Rob says that a day or so after dropping Sydney off, he stopped by to bring her some food. This article probably has more relevant details of any other media report produced since that time. After this one, information flow seems to have been censored, stopped or in some other way altered....i.e. via "spin."
If you look at the missing info vs Sydney's self reported athletic profile
Sydney West's Women's Volleyball Recruiting Profile , they even differ. Sydney said she was 5'11'' and 120 lbs. That would put her BMI at 16.7 which is considerably underweight (underweight is < 18.5). When I look at her photo probably taken in the May 2020 time frame in front of the kitchen cabinets, the one with the I am Berkeley bound sign, her face looks to me narrow and almost gaunt as if she weighed even less. She looks unwell to me in that photo.
Sheriff: 19-year-old UC Berkeley student from North Carolina reported missing in San Francisco shows the initial Missing Persons report. The upper photo shows a much fuller face, but the lower right photo, Sydney's face is very narrow (kitchen cabinet photo).
In earlier photos when she was in high school her face seems fuller and she looks healthier. For example there is a photo of her with some vehicles in the background where she looks to be on a porch that looks to be the upper photo in this Missing Persons report in the above link from the Orange County Sheriff's Department. Her face is much wider then. It could be that there is an issue with the resolution or the camera angle that distorts the photos; however, if that is not the case, toward the end of her gap year though, as indicated by the kitchen cabinet photo, to me she looks like a different person. The upper photo and lower right photo are strikingly different. Her narrow face in the lower right photo to me looks like she is much thinner than the top photo. It could be that Sydney had become so depressed that she was no longer eating properly. Perhaps that is why her uncle brought her some food to the dorm.
After that initial article in the newspaper, it appears that there started to be some strange PR campaign of self-produced videos, vigils, and other carefully curated internet activity that looks like a political campaign. Perhaps that is when Amy Weiss and her husband Peter Kadzik became heavily involved. You can Google them to see that they have quite a history in politics and "spin" to put it mildly. Amy Weiss is the PR person listed on findsydneywest.com. Peter Kadzik is a former assistant attorney general for the Department of Justice and lobbyist. Both have a video on the Find Sydney West Facebook page.