Hi Mr X and dave. I know what you are talking about. In Windows 10, the folders had previews shown. In Windows 11 this has been removed. It is really a step backwards I think in 11. However, I don't mind having no preview on the folder. Anyhows, I think 11 is still a work in progress, if there is enough guys want previews Microsoft may bring it back.
We can still however customise the folder, and put an icon on the folder if we want to. Like I have a folder I have called Music (not the Library) and I put a music note icon on it. And on my Astronomy folder, I put an icon of a planet on it.
Cheers .. take care ...