I have.

When I moved in with my wife in Kentucky, I asked them how much was they paying for which speeds and when I showed them the actual speeds was so slow nothing was loading up, I called the ISP and numerous issues was fixed from the phone jack being burnt up to the nodes being faulty.

Telling the techs what you done helps pinpoint the issues especially if it’s their lines going to the nodes.

Very weird you have this issue on IOS. I have 4 IPhones that auto uploads without issue on different IOS versions. Is your server instance updated? I found that if nextcloud is outdated but the phone app is on latest version will have some issues.