I installed sections-compatible Debut theme from this doc: https://shopify.dev/tutorials/develop-theme-get-started-with-online-store-design-experience (point 1.)
I have online store design experience preview enabled for store but when I try edit product page I see something like this:
I see that frame sections (header, footer) working well but I can't add any content sections from list (there's no option to select any content section). I see that in section folder some sections exists.
I found similar problem here: https://community.shopify.com/c/New-Online-Store-Design/Not-seeing-any-sections-or-settings-in-Devel...
but solution in this case was enabling sections in "Page Setting" and installing compatible version of Debut theme.
In my case I have up to date (I think) compatible Debut theme and when I trying display "Page Settings" for product page or other pages (404, cart) by clicking to three dots I see that this settings can't be load (loader spinning all the time without results).
This does seem like an unusual issue- could you share your store URL and I can try to see what is happening here?
Shopify | Developer Community Manager
I think now all functionality works as expected. This was mentioned and solved here: https://community.shopify.com/c/New-Online-Store-Design/Not-seeing-any-sections-or-settings-in-Devel...