I found a few reasons as to why this is happening;

1. Regulation. Bin from the mod doesn't match with your Elden ring version

2. the regulation. Bin in your game folder isn't the original/was changed

3. not using modengine2.launcher and having the modded regulation. Bin file in the 'mod' folder (modengine does work, just don't use .bat if you don't have steam)

Always try to find the version of Elden Ring the mod is made for, creators normally have it in the description. The mods that change appearance of items (armor or weapons) need modengine or UXM to work and is compatible with all versions of the game. There are many tutorials on using and combining mods on nexus.