as an aside, if you think Arceus looks better then I really wonder how selective you're being with your criteria lol
Arceus worldmaps are barren heightmaps with low res textures bolstered only by unusually high mipmap and specular highlights. Those maps feel amateur compared to what I've seen in Scarlett, which - for all of its issues with pop in and low res textures/low lod - feels like it boasts a much more intricately designed aesthetic throughout.
Pokemon models are higher poly in Arceus but that's about all I'll give Arceus - even the textures are just repeated tiles painted on the ground like something out of Sims, and the shader model in Arceus is simply worse by FAR than what we've seen in Scarlett, which boasts a rudimentary PBR pipeline and newly implemented lighting techniques that together help to create a much more cohesive and varied look.
Art style is arguable - I love Arceus art style even if the visuals are decidedly simple - but I think Scarlett and Violet's overall aesthetic is very nice and simply more well rounded than in Arceus despite its obvious flaws, performance issues, LOD issues, low res textures, etc. Arceus looks like an enhanced 3DS game in a lot of ways
They really gotta fix the performance though