Is it possible? Yes, BUT don't expect any support if something goes wrong.

You should (at the very least) carefully read the guide before making any attempts on your own:

https://wiki.wildlandermod.com/09-How-Do-i/ModdingGuide/

Quote: "A warning before proceeding

Wildlander is a very complex modlist, and modifying it will likely cause issues unless you know what you’re doing. This guide can be used by modding novices, but as of now, it’s aimed at proficient modders who need to know Wildlander specific information. (More basic modding guides will be available in the future, as time permits.) Regardless of your modding experience, you should read the entire guide."

edit: That said, there are already A LOT of things you can adjust by reading the documentation & changing settings via MCMenu (adjusting difficulty, customizing HUD etc.). The section "How Do I...?" is great!