Display Template not showing when editing search results Sharepoint online

I have already worked with display templates and I have managed to implement a custom search result on another site within the Same Office 365. However, on a recently created site, I am finding a problem with seeing the display templates when editing the search results web part of a new search result page.

Around 3 days ago, I noticed that the ‘Sharepoint Server Publishing Infastructure’ was not set to active. In fact when uploading the Display template html files, the Javascript file was not being automatically created. I activated the feature, and the Javascript files are now being created, but I still could’t see the display template when editing the ‘Search results’ web part. I waited 2 days, as I recall something I had to turn on for something similar did not take effect immediately, but still, nothing.

Why does it work on one site, but not on the other? What other features could I have missed to turn on? What can I try?