I can do the things which are discussed in the above listed thread like saving as webloc, or exporting as PDF in Safari, but particularly the PDF solution often results in black images in the PDF. So for the app I use here as example:
What I have for now decided on doing is screen capturing the page as image in the browser (Vivaldi for example has a handy function for this), importing this in DEVONthink and then converting it to a searchable PDF.
A bit cumbersome, but all app screenshots come through and it is still searchable.
This yields a formatted note, converted from a bookmark.
Use Share > Copy Link on an App Store page, then Command-N to create a new bookmark in the targeted group. This will be converted into a formatted note. On the Mac, this displays as a quite accurate representation of the actual page.