So a friend of mine linked me
an image since they're aware of my love of women in practical armor, but the moment I saw the picture, my mind started picking it apart. After several rather pedantic discussion points - Why would a centurion be using a spear? That's an auxiliary weapon! Where's the scutum? Why an arming sword, rather than a gladius? Is that custom-made armour for Legio IV? Nice touches with the classic style apron and segmenta! - the talk turned to the fact that, if nothing else, the image portrays a centurion of traditional Western Roman aesthetic but with medieval military gear equipped. And that leads us to this point.
Under what circumstances do you think that the Western Roman Empire survives, whilst the Eastern Roman Empire collapses?
Obviously the ERE only survived until the Ottoman conquest of Constantinople, so let's presume that a theoretical surviving WRE survives until approximately the same time.
Bonus points if the WRE keeps a "Roman" character instead of "going Greek" like the ERE did - enough that traditional Roman aesthetics would survive in its military equipment a la the aforelinked image. Specifically, it shouldn't be heavily influenced and colonized by barbarian mercenaries and generals and such, as it was towards the end of its OTL lifespan.
Further bonus points if you can have it survive
without adopting Christianity or any other new religions in full; syncretism is fine - probably inevitable, knowing Roman religious history - but the WRE should optimally still be as pagan as possible under this bonus mission.