you don't recalculate all of the scenarios every move (stroke / point) like you do in chess (would be very high on your spectrum, is there any sport that comes this close?!), but you do reassess what you're doing as the match progresses if your plan or intuition is not working. especially if your service games are under pressure as in the game you refer to. As you're discussing degree, for a sport, tennis has a lot of strategy. Can you think of many other sports that have more strategy?
Not to generalise based on your example match, but why didn't the player your refer to not hit some kick/slice 1st serves to be less predictable and make her main flat serves more effective as a result? That's a strategic option, just because it wasn't used in a particular match doesn't mean that there is little strategy in tennis. Would the opponent have responded by hitting more winner return of serves? Did the player think this far ahead and come to the conclusion that this strategy is sub-optimal? (we're in game theory territory now). See what I mean? Anyway, that is WTA. the mens game shows strategy in a clearer manner as they play longer matches and have more variety on tour. It's more obvious.
check out the mixed doubles semifinal being played now, or the final if you read this too late. Lots of strategy on display there. Nearly on a point by point basis as you can see due to the communication between teammates. You can't observe the internal conversation in singles and have to infer it from play.
Disclaimer: I'm NOT a coach...
Real tennis: https://www.youtube.com/watch?v=yDqnkLJ9BtM