The Ellipsis 8 (and 10, which is basically the same tablet, but with a larger screen) is a basic tablet, not a lot of RAM or processor speed, or internal memory. So, some apps won't run well, or at all, no matter what you do short of using a different tablet.
Keep only one app open at a time so all the resources can be used for that app. Move videos, photos, music, and other data to an SD card so internal memory is maximized. Disable or uninstall any apps you don't use.
The only real resolution is to invest in a "real" tablet with enough internal memory and RAM to support the apps you want to use.