Long Halloween Omnibus or Individual Deluxe?

TLDR: Newbie don’t know which versions of comic books to buy and seeking advice.

Brand new to this comic thing. Thank you in advance for the help.

Searched, but I couldn’t find anything about which versions of books to buy. I find it very confusing on which versions of a story to buy.

Let’s use Long Halloween for example.

Should I get this Omnibus? It looks to include the first two major stories, LH and DV, and some side stories like When in Rome https://a.co/d/6bH3uMG

But then, it looks like I’ll have to buy Last Halloween separately right? https://a.co/d/9ajEykS

If I have to buy Last Halloween separate, does it make sense to buy Long Halloween and Dark Victory themselves? Here’s two links I’m thinking.

Long Halloween https://a.co/d/3cMbx5L

Dark Victory https://a.co/d/6rxdQB8

“If you’ve come this far, maybe you’re willing to come a little further.”

I’m also considering buying Maus, All-Star Superman, Killing Joke, Favorite Thing is Monsters, Batman Year One, and League of Extraordinary Gentlemen, but I don’t know which versions of that to buy either. Want to make sure I’m not missing out!