Don’t think the speed of your internet will make a difference, I get anywhere from 15 Mbps Up/Down to 3 Mbps Up/Down and the “Failed to Upload” is very random.
I run on a cellular router with a Mesh WiFi system and the nearest cell tower is 7 miles away through the Eldorado National Forest.
I can go for weeks without the “Failed to Upload” then other times it happens almost daily.
I blame Wyze servers for the issue, and even rebooting the App does not help.
It rained real good last night so all the trees have plenty of moisture which is attenuating my signal today and I have no “Failed to Uploads” so far today and last night.
Today’s dismal internet speed: