IMO, Monkey Island 1 & 2 are already at the top of what the genre has to offer and a model to many other titles, most of which have much worse puzzle design. If you don't enjoy checking out your surrounding for things that could be of use to you and figuring out puzzles by combining them, I fear your experience with most other p&c adventures won't differ much from the experience you've already made, unless their themes and stories are more interesting to you, but in that case rather than ask for random recommendations, tell us about your expectations - what kind of stories would be more to your liking?
Without any idea about what you like, I'd concur with the suggestion to try the
Blackwell games. They are similar to Monkey Island but they are a bit more focussed on the story-telling than the puzzle solving and are therefor a bit easier and could be more motivating to you, also because the stories are a bit more serious and less wacky.
Jolly Rover is an easy one, too, but a Monkey Island clone, so you'll probably find its themes even more juvenile and less interesting. But it's one of those modern indie adventures that has in-game hints and clues, if I recall correctly, same as
Machinarium (which is quite puzzle heavy and not that easy though),
Hector: Badge of Carnage or
The Inner World.
Or if you don't like the puzzle mechanics at all, try some different breed of adventure games like:
- the interactive movie style adventures by Telltale (e.g.
The Wolf Among Us) or other studios (
Life Is Strange,
Dreamfall Chapters). Less (or next to no) puzzles, no pixel hunting, more dramatics/cinematics, more action (often in the form of Quick Time Events).
Fahrenheit/Indigo Prophecy could be considered an early form of them, you should check that out too, it has a gripping start, but also its share of flaws.
- the story/exploration games that are derogatorily called "walking simulators" by some, like
Gone Home, in which you mostly just move forward, learning the story by examining your environment. Or those that are close to visual novels but with more interaction, like
To The Moon.
- adventures like
Jazzpunk, or
Botanicula in which you just interact with things in very simple ways to make funny stuff happen
You most probably won't need to consult walkthroughs for these.