Are sandbox games easier to design?

I checked a video review of "western legends" and I have seen very few games like that as board games. Apparently they are called sandbox games and they are close to certain experiences I had in video games. I like the idea because it allows players to do sub-optimal actions to express their creativity.

Now, I was wondering if those games were actually easier to design. It feels like a game design that you could start with little things, then gradually add stuff to the game as the ideas comes in until you reach saturation.

Which is very diferent from other game which feels like trying to assemple a puzzle in your mind and place all the pieces at once on the board, then start over if it does not work.

I think I have a few game ideas in my list that could fit for a sandbox game. I stopped the design because the battles were too long and because there was too much data to record. But maybe it's because I approached the design the wrong way.

Maybe I could just have a pawn move around the map. Then add features and complexity as the game progress until it reach a point where adding more would be unplayable.

For victory condition, the only option seems to have many various ways to score points and reach a score limit to win (like western legends). Or play X turns and the most points wins.

I am trying to find what could make sandbox games easier to design. Or if it's just an illusion.

One thing that comes to my mind if the splitting a resources. A game with a limited set of action will split the user resources among those actions. Adding actions will dilute the invested resources between the actions. But in a sandbox game, it does not matter, because you do not have to make all actions in the first place. It depends of you goals.