I had same issues with my site loading time on desktop it was great but wix Mobile let it down - most visitors will not wait more than 2.0 sec for a page to fully load before they just move on to another url, stats suggest you lose upto 70% of clicks when visitors are left waiting for pages to load, i tried everything to improve my load time on wix mobile - i got so frustrated in the end i took the plunge and went over to wordpress.
If only wix mobile performed better i would have stayed with them, Wordpress was the right move for me, i lost my seo i had built up but the switch paid dividends, my site now fully loads between 0.5 & 0.7sec on Mobile and tablet using a couple of plugin’s to leverage browser caching, minify HTML css and java requests and optimizing images has made massive difference to load times.
I like wix for it’s ease of drag n drop page design if they ever sort their mobile side out i would not hesitate to return - with google now making mobile page speed a top criteria towards google rankings. Wix needs to up it’s a game or lose valuable customers.