All this tactics game talk is reminding me of Triangle Strategy, which I got most (I think?) of the way through two years ago before more or less ragequitting. The difficulty curve on that game was pretty rough: Medium was a guaranteed victory on every mission, but Hard was practically a guaranteed wipe every time. I simply could not figure out what the game was going to consider "good" strategy and what it was going to punish in unexpected ways. A real hair-puller.
I wanted to like the game but it never "let me in." Which is a pity, because it reminded me so much of my hours and hours of enjoyment playing Final Fantasy Tactics: Advance on the GBA.
I tried the original Fallout once off a GOG Games sale, but since I had played Fallout 3 already I was not in the right mindset for the wildly different gameplay. I think going back now I would be much better prepared for what to expect!