Sony has made some changes to the layout of the PlayStation Store of the PlayStation 5, making it more difficult to find demos. If you can’t seem to find them, then you can check out this guide at Seeking Tech.
Use the following video as a visual aide:
Step 1: Open the PlayStation Store.
Step 2: Scroll to the bottom.
Step 3: If you don’t see the Demo section, switch between the Latest, Collections, Deals and Subscription tabs to refresh the pages.
Step 4: In the Demo section, use the Sort and Filter menu to help find what you are look for.