I haven’t buit many robots but honestly the claw bot was the hardest thing so far since I was and still am a beginner.
Hardest thing to build is the confidence to ask for help
my current robot,took a whole month.
A good scissor lift is pretty challenging
But… why would you ever build a scissor lift?
For the challenge of doing it? To quote JFK “we choose to go to the moon not because it is easy, but because it is hard.”