Since being introduced to Pokmon Scarlet & Violet with The Teal Mask DLC, there is only one way to evolve Lampent into Chandelure. Along with their base form, Litwick, these make for a unique Fire and Ghost-type line of Pocket Monsters. Litwick evolves into Lampent at Level 41, but one key item is necessary to pull off the final evolution.
https://screenrant.com/pokemon-scarlet-violet-how-to-evolve-lampent-chandelure/