I agree about Root.
However, all three of these apps are among the most expensive digital boardgames there are because the underlying games are so popular and the apps are new.
I like all three boardgames quite a bit.
But they cost 20,- on PC and 10,- on tablets. For a little more than twice the money of the PC version you can get the paper versions of any of these and they all have good solo-modes (especially Wingspan and Spirit Island)
To verify my discounting of Wingspan, I’ve just started a game and it seems like they’ve made some improvements since I last played. There is now a different mode of display that gives more information at a glance. Still, I find it a bit cumbersome in comparison to the physical game.
Spirit Island is a game with some table upkeep/book-keeping (see the thread) but the app makes seeing all the information so difficult that I keep making unfixable mistakes (once a random outcome has been revealed there is no more undoing). I love SI but I do not enjoy the app much (and I backed it on Indiegogo).
edit: and to add one more all of these have a LOT of information that need to be displayed and I would argue that they need at least a big screen of a laptop or computer. I’ve played Root recently on my tablet and it just doesn’t fit on the screen.