Some think, it's too easy, some think it's too difficult - there is a solution for all of you!
The first maps and suspect sets are naturally a bit easier to allow understanding the core game mechanics and getting into the game. Clues are placed closer to the player and winning the game should be easier early on...
... still: it is a game where you need to find clues, compare it against the suspects, their pictures, their background stories. Sometimes you had unlucky dice rolls, sometimes you did not find enough (useful) clues, sometimes the (too few found) clues were not conclusive. You can and will fail, it is part of the game. Same as you cannot win 100% of Slay the Spire or Poker runs.
And then there are new, larger maps and larger suspect sets that you will unlock while you gain XP and level up. Each will have new challenges.
Ultimately, you can choose the maps and suspect sets, which fit best to you and your preferences - the choice is yours!
If you want to challenge yourself: Pick a larger map like the City or Airport map, the latest unlocked suspect set, and try to win 10 times in a row... Good Luck!