I would need to see the parameters that study used to conclude definitive outdoor transmission. A study done by the South Koreans, who had rigorous and intrusive contact tracing in place prior to the study as well as high quality testing for positivity, found that out of 407 patients testing positive for WuVid, 406 caught the disease from indoor exposure to others already infected. The one remaining case could not be definitively attributed to an outdoor exposure but it could not be ruled out
Here is a literature review about outdoor transmission. I didn't pursue the reviewed studies. It seems everybody agrees the level of outdoor transmission is low.
https://academic.oup.com/jid/article/223/4/550/6009483