Regardless of the resource pack or the number of mods (even if you deactivate ABSOLUTELY EVERYTHING apart from the AutoHUD mod) in version Minecraft 1.21 NeoForge the Pause menu and the Inventory menu are not displayed at all, only the background blur and the cursor are visible and it doesn't matter the settings of the mod or whether you activate the hotbar or not.

I can replicate this on 1.21; I cannot replicate this on 1.21.1 with the latest NeoForge loader. Apparently there was a change between those versions. I'm afraid I will have to drop support for 1.21; see if you can upgrade to 1.21.1 for your installation, as that appears to be the currently recommended version for NeoForge modding.

If you are on 1.21.1 already, make sure you update your NeoForge loader to the latest version.

(If you can replicate it still on Minecraft 1.21.1 with NeoForge >= 21.1.119, feel free to reopen the issue)