A funny thing about the widespread “Jon is stupid and keeps making dumb choices that lead to him almost dying” take is that if you were to really look at his behaviour, he very much acts in the way the “horror characters are so dumb” people would want him to act.
He doesn’t jump to irrational conclusions, doesn’t dive head first into danger and instead prepares for it as well as he can etc etc. He’s very distrustful of everyone and everything due to his paranoia, and tries to do as much research as possible before heading into the unknown.
You just get annoyed at him because you, as the listener, already know the things he’s researching, and possibly already know what his actions will result in. No, his fate couldn’t have been avoided if he had done something differently. The only way Jonathan Archivist Sims’s fate could’ve been avoided would be by entirely rewriting his character story from at least the age of eight. Goodbye Mr Spider!
What if, instead of Sasha, it was Martin who got killed and replaced by the Stranger in s1?
Think about it. Martin was sweet, always helpful. You couldn't say a bad word about him. He was inobtrusive and caring. But what did you actually know about him? What are his hobbies? His passions? What was his history? After all, most of the information he put in the Institute's paperwork was made up.
Imagine the Archives crew finding out the truth about him being gone and seeing that they never actually knew him, not even when he was there. That he was a replaceable figure. Good, sweet, caring Martin who never shared what was on his mind. Martin who was always so plainly kind without actually contributing much to their lives, passing by unnoticed not because he was disliked but because he wanted to. Was he ever truly there? Do you even know who the person you're mourning was? Or is it just an image of him, an image that HE created of himself and sold to you.