Some mods will have dependencies. Which are other mods that provide a collection of assets or configurations.
For example, Norbytes Script Extender, Compatability Framework, ImpUI, Baldur's Gate 3 Community Library, Mod Configuration Menu (MCM) etc.
These will need to be downloaded and placed higher in the load order than other mods that utilize them (Sadly, the in-game mod menu does not allow for adjusting load order. You'd need to use something like
BG3 Mod Manager in order to manipulate load orders)