I would say its still pure Android.. If you look at all the features that was added on to Pixel they were all app features rather than the android feature like the pixel launcher, unlimited storage&smart storage(features of google photos app), google assistant, wallpaper picker(works with pixel launcher as a seperate app), dynamic calendar(Pixel launcher feature) etc
The only thing google changed to the android itself are the Solid navbar icons with home affordance for Assistant, SysUI accent color theming and New setup look and feel