Is there a word for writing nonsense in a way to create the illusion of deeper meaning?

mumbo jumbo

senseless or pretentious language, usually designed to obscure an issue, confuse a listener, or the like.

From a David Berlinski lecture:

" ... some banal thoughts buried in mathematical mumbo jumbo. Now, personally, I have nothing against mathematical mumbo jubmo: it's my stock-in-trade! But at the same time, let me tell you, I can recognize a co-conspirator."

https://www.dictionary.com/browse/mumbo-jumbo?s=t

The word "illusion" already describes a false sense of reality. That is why magicians are said to do 'illusions' with their magic tricks. Another term might be mirage as in a desert mirage.

The Beatles songs are great because their lyrics combine wit, wisdom, fun, depth and transcendence like Lucy in the sky with diamonds walking the yellow marmalade road. This, together with the same for their music which had many moods and registers. They didn't follow fashion - but made it. And their songs remain timeless which is why they are, and will always be, perennial and evergreen favourites.

When their words don't make "sense" as you put it, this is because they were using their words as yet another musical instrument. After all, do musical instruments make "sense" as words? No, of course not. But this is because they resonate with the heart and not the head.

Pretentious fits. It means "to pretend". Though, people tend to only call things pretentious when it has failed at pretending so it has negative connotations associated with it which may not be what you're looking for if you're going to use a Beatles song as an example (or maybe you are? I guess it depends on whether you like the Beatles or hate them.)