I think that WB should not be way to complicated and that it should be proportionate to the length of your novel.
It should be made so that it's easy for readers to comprehend.
Having said that, I wouldn't say that the WB in my novel is vast and deep in comparison to some like LOTR.
However, I would also like to add that it's also important to consider how detailed one's WB is.
You would be surprised what you could do with a small cast of characters/a low number of countries/a shallow magic system/ etc.
I estimate my novel to end at around 600k words, which is pretty short compared to the majority of other novels.
Nevertheless, I have about 100 named characters, 14 organizations, and a half-opened magic system.
How?
Well, some of the most important battles and events in my novel aren't even described since they happen outside of MC's pov.
Not even 5 of my characters have their biggest fear or favorite whatever known.
The most crucial thing a character needs is a goal, purpose, and ideology.
Just with that you can put those characters in a desired setting and the chaos will emerge by itself.
There are around 7 side characters that have a bigger impact on the world of my novel than the MC, despite living in the same era as them!
TL:DR My novel's WB is not deep by what the definition would be, however, it is very deep considering all the things that do happen and are present and yet DID NOT make it into the wall of text. I left it out to avoid filler and unnecessary information.
Remember, my novel follows the MC, but that doesn't mean that the same amount of things don't happen to other characters.
Some of those are vaguely mentioned while others are hinted.
