The HDRIBackdrop plugin consumes around 200 MB of VRAM by default. When the plugin is enabled, Unreal loads a default HDRI texture into VRAM, even if it isn’t used in any level.
Hey there! It’s worth checking the reference viewer on that asset to see if something (like a material) might be pulling it in accidentally. I know I’ve done that myself in a previous project where I thought I was innocently using that cubemap without realizing how large it is.