Contacted the support team about this issue, they said
Thanks so much for bringing this to our attention. This is currently a known issue with Editor X and Wix Stores, unfortunately.
Rest assured, I’ve passed the feedback and the urgency of the situation onto the relevant team , but I do see you’ve also come across the temporary workaround of sorts that many people employ in the meantime (using grid galleries side by side), like you’ve done on some of your custom stores pages.
So i think we have to wait until the problem is solved and they fix there store layout, what i recently found in a wix template is that the “basic” wix (not the editor x)does support this feature in the store settings (the two columns function). But then offcourse the layout is not what it is in editor x for the rest of the site.
and we can vote for this feature to keep us updated when visible…
kind regards