Seems to be working only without domain name tied to Wix site. 100% works with premium + free wix address as of Jan 10th 2023.
location ~ ^/(.*)$ {
gzip off;
proxy_ssl_server_name on;
proxy_set_header Accept-Encoding "";
proxy_set_header X-Forwarded-Host "";
proxy_set_header X-Forwarded-For "";
proxy_set_header Referer https://username.wixsite.com/sitename;