This is one of those silly little niggles that happens often enought that it annoys me:
→ I wish I could 3 or 4 finger swipe between apps running on my mac, just like I do on the iPad.
I guess I could do that if I ran ever mac app as a space, but spaces always seem too complicated and confusing.
If you use your apps fullscreen that’s precisely what will happen.
I do not know how to make this happen. I took a look at what is available in Better Touch Tool and I did not see any specific action to switch apps by swiping. There may be a way to have BTT trigger some other tool to do this. So if you are comfortable with Mac automation tools you could look into this further.
One reason Spaces seem confusing is that Apple turns on the “Automatically rearrange based on most recent use” by default. Go to System Preferences > Mission Control and uncheck that first option if you haven’t already. Then spaces will stay organized.
And one thing I do is specify that an application open in a specific space. So Mail always opens in Space 5, and Photoshop always opens in Space 4. So I always know where they are. And I can swipe between spaces as you note.
But unless you then set up a space for every app this is not a general solution for what you want to do with the swiping. And more spaces means more swiping. But this may help make spaces a bit more useful for you. I find them quite useful for organizing my workflows.