What are potential candidates for an out of the box Intranet solutions based on SPOL

As a software development we built our own pattern for use with Office 365 based on the PnP and previous customer experience. The tricky part was finding a balance between delivering a solid information structure and user design with the flexibility for the customer to make changes and for us to do upgrades. We have also been looking at a few products on your list such as Unily and Attollo but haven't drawn any conclusions yet on if these have a better approach although they do have solid foundations found in common intranets.
I would say you need to do lots of due diligence including trying these in test tenants first. Consider how flexible they are for you to add apps, change page content and add new sub areas. How much of the design can be changed to suit your company brand with O365 pattern guidance. Upgrades and ability to use the latest O365 features would be paramount so you don't restrict your usage of O365 features.