Title is it possible to make something similar inside the homebrew options. I'm still trying to get a good handle on the tools and want to know If it's possible.

That depends. What exactly do you mean? The Book of Shadows is essentially a lot like the Ritual Caster feat. So you could totally make a feat that would function pretty much identically to the book of shadows. If you wanted to make it as a magic item that would be more challenging.

I meant like creating a feature like that with the auto-expanding spell list like the book of shadow or the ritual caster allowing the player to add to the spell list.

Never mind figured it out appreciate it

Cool. If you need any additional help don’t hesitate to ask.