Interesting questions
As to the first one..
Yes, Bitcoin will truly preserve the information. The laws of physics prevent any changes to said information. Nostr as well but it's more complex if you wanna make sure it's preserved.
Information will always remain open to interpretation, that is simply human nature and should not be considered a problem.
If we all had the same thoughts it would be a dystopian nightmare.
That aside, the importance of unalterable records is not to be underestimated.
Especially with AI's biggest threat, which is to alter history as it, or rather the programmers, please.
Parts of Bitcoin's technology is the antidote for this.
As to the second question..
There's too many ways to answer this one so you'd have to reformulate your question if you want a proper answer from me, as I first need to know how you define the word truth for yourself, to give one example.
I'll say this however:
Lies can also be put on Bitcoin's timechain, but it is unmistakenly the truth that this lie was in fact put on the timechain, at that specific time (block height). (In form of information that is, transactions are irrefutable truths)
Critical thinking will always be necessary.
Again, unalterable records is something entirely new to humanity and it will be interesting to see how it plays out.