How many soul-crushing deaths should I expect before I beat the game?
That depends entirely on how long you stick with trial and error rather than consulting the wiki. If you play exclusively without looking things up, it then depends on how much you're willing to savescum. If you completely refuse to consult guides and start over from the beginning after every death, it's very likely that you will never beat the game. If you avoid the guides, but save the game every couple months and savescum until you find a way to avoid each death as it happens, you can probably beat the game in under a couple dozen deaths. Probably.
The worst of it isn't the dying part. Deaths are consistent and predictable. The problem is that even when you know a death is imminent, how to avoid it isn't always obvious. Even knowing which skill is tested before you die, you won't know
how much of that skill is required. So you might restore to a previous week, train the required skill, resume and die anyway because it wasn't enough. Then restore to two weeks prior, train that skill both weeks and it's still not enough. And then restore to three weeks prior, train that skill all three weeks only to discover that after passing that particular skill test, there's another check for a different skill afterwards that you fail, so you die anyway. So...you then roll back four weeks...you get the idea.