This is an annoying .... Why do you have two confusing viewer ?
So in the AGOL, There are 7 menus at the top of the AGOL

So when you are inside your My content .
Now when you have all the stuff in the Title ....
On the far right side :

Now you see the three dots above ?
right click on them : See Here in the pictures

See yellow circle : Proposal to change from "Open in Map Viewer to " Open in Map Dashboard Viewer"
Proposal to change from " Open in Map Viewer classic" to "Open in Map AGOL Viewer"
Do you agree with me or not ?