If a person can lead a fulfilling life without following sports or reading non-Jewish literature, if they can get all they need from the world of Torah, then that’s great. If they need something else, I would not call that a b’de’eved; for them it’s a l’chatchilah, in the same way a lactose free diet is a l’chatchilah for someone who is lactose intolerant. A bocher who does not have an intellectual bent, but learns as much as he can and gets a job as a contractor is just as much a l’chatchilah as someone who learns in kollel.
As for Tolkein, although the author was a strongly believing Christian, there is no overt religion in the Hobit or The Lord of the Rings. The latter books, published after Tolkein’s death, do deal with religion, but AFAIK, in a Theist, not-explicitly Christian way. There is some love interest in the Lord of the Rings story, but (as far as I remember), not even a kiss. The books are informed by a generally accurate moral compass.
My kids were interested in the Narnia stories by Tolkein’s friend CS Lewis, and I was reluctant to let them loose on them, since they are an obvious allegory for Christianity. Obvious to me maybe, my kids saw it as just more fairy stories.
Which reminds me of a taxi ride with my eldest son when he was just after bar mitzvah. On the streets of Jerusalem we say a priest in his robes, prompting my son to ask me, “What do the Notzrim believe?”. I gave him a brief explanation of the idea of the man-god and the idea of Yushka being a korban to be m’kaper for everyone’s sins. My thirteen year old listened intently, looked thoughtful for a minute, then cracked a sly grin, “Ha ha, you don’t fool me Aba, what do they really believe?”!
For my tahor son, raised in Jerusalem, it was literally unbelievable that anyone could believe such things!