Help Google Play Store Slow or Not Installing Apps


Envizen V100MDT Tablet - Rooted - KitKat 4.4.2 - Kernel 3.4.67
LG L34C - Rooted - KitKat 4.4 - Kernel 3.4.0+
NextBook Ares 11.6 Tablet - Not-Rooted - Lollipop 5.0 - Kernel 3.10.20-x86_64_byt

Seems to me, like Google Play Store has been having issues last few days.
I can't get apps to install, without taking forever to do so, or stopping and giving errors.

Yes, I have tried ALL the ways and so called fixes that Google and other sites tell people to try, to no avail.

This is on 3 devices, tested on 4 WiFi networks, so it's not a device or network issue.
When try to install, it takes a very long time, to even install a small 5mb app.
Used to take seconds, to download a 100mb app.

As usual, no help from Google on this issue.
Tried via their product forums, and live chat support.