The English expression “It is one thing to ... but another to ...”

I’ve just used this expression in the sentences below, and I wonder if my use of it can be somewhat misleading. More specifically, I’m talking about the “to” in front of the “fully appreciate”.

I’ve used it to mean “in order to”, but the usual pattern of this expression seems to dictate another interpretation:

“It is one thing to passively learn about … but **to **fully appreciate how and when … is quite another”.

Here, the “to” is used to form a subject noun phrase instead. What’s your take on this?
>>> “It is one thing to passively learn about all those various commands in JavaScript by poring over online materials. But **to **fully appreciate how and when to use each one, I need to try them out in my own code and have them corrected by someone in the know.” <<<

They’re both proper usage of the words, but you’re saying different things.

“It is one thing to passively learn about Buddhism but to fully appreciate the complexity and meaning of Buddhism is quite another.”

“It is one thing to sit in class and listen to the teacher. But to fully appreciate Buddhism, you have to devote yourself to a lifelong study of this philosophy.”

These sentences seem clear and easily understandable to me, and don’t jar against the expectations of native English speakers.
And that’s all you really want, so these are fine.

Great comparison, indeed.

Just to answer the OP’s question: The “to” is absolutely necessary. The sentences as given are perfect English usage.

OP says, using “to” with the meaning of “in order to”.

Here, in Dingbang’s first example [1], “but to fully appreciate” does NOT mean “but in order to fully appreciate” – it just means what it says, “but to fully appreciate”.

In the second example [2], “But to fully appreciate” DOES mean “But in order to fully appreciate”, and this is a perfectly cromulent way to write or say it. This appears to be the usage that the OP is using, and correctly so.