I've installed Forge 1.16.4, as well as one mod (RPG-Hud [Forge]), one mod pack (Craft to Exile [Harmony]), and Optifine 1.16.4. Unfortunately, when I boot up Forge, it's only displaying Minecraft and Forge under my Mods section. The only potential discrepancy I found was RPG-Hud being version 1.16.3, but as far as I understand this shouldn't be causing the issues that I'm encountering.