My iphone is downloading apps very slow

If you have tried using different internet connections setttings and the problem still occurs, it could be related to the apple servers. You can check the servers status of apple on this website : Apple Servers - System Status

This happen to me too. But the thing is that when I watch YouTube it is fast. I have optical fiber at my home speed 500mbps. I thought it was router so I switched to my 4G network, it is still the same.

The same happen in Apple TV. When I open up my Movies Itunes, the image doesn't load at all. When I switched to YouTube, the movies even play at 4K without any stuttering.

I've checked. All is green. Still the same lagging and even when I want to install the apps it can takes minutes before the installlation confirmation dialog pop up. I even log out from app store and login again still it is the same. I've never had this kind of issue before. This had been ongoing like few weeks already after the recent iOS update.

It depends only on your LTE or wifi download speed and on Apple servers available speed (they might be very busy), keeping in mind that, beyond downloading, apps needs to be installed, often reindexing the existing related data.

Regards

Giulio