I don't know how to put this, but I will try to be precise, so the issue is addressed properly
My SharePoint List has a total of 29 columns when I created a PowerApps from the SP List the data is not showing in all the three screens (Browse, Detail, Edit)
Out of 29 columns, 12 columns are People columns.
When I delete last 2 columns (2 People columns) then data is coming properly in PowerApps (27 columns now).
When I add 2 new Text Input fields then data is coming properly (29 columns again)
So, at this point my understanding is that PowerApps only show data when SP List has no more than 10 people columns (I could be wrong too).
I was not able to fix this.