The Democratic electorate in Connecticut is whiter (but still decently diverse), more liberal, and more college-educated and wealthier than the average state and I'm supposed to believe Biden is ahead by 20+ points. Calling garbage on this one.
It's an older, heavily suburban, and well-off state. I don't see why it's hard to believe.
The only thing going for Biden that you described is older. If national polls are showing a dead heat and Elizabeth Warren is shown to do well with well-off demographics (which, she is) why is she doing so bad in Connecticut?