Hi,
Do you want to know the differences between the Basic Search site and the Enterprise Search site in SharePoint online?
Basic Search center only allows to search within lists or within sites. Search results are displayed on a system page where you cannot customize easily. You can only edit the existing search page and search result page and we cannot add
more pages of our own to it.
Enterprise Search center allows to search across site collections and even web applications. You can author our own pages, and overall much better control over searching in general. In enterprise search center, video search is supported
and center provides Navigation Verticals. Also, you need to enable two site level features: SharePoint Server Standard Site Collection features feature and SharePoint Server Publishing Infrastructure feature.
Feel freely to reply if you need more help.
Thanks,
Dean Wang