Okay...
1. In the Blinkova vs Rybakina match we got to see two longtime colleagues whom consistently faced one another throughout their Junior years. Perhaps the pair could be placed in the "nemesis" category. Each knew the other's routines and habits. Thus, an amazing battle ensued.
2. If fluctuating Top 20 rankings is a new concept to you, are you even paying attention? This is going to be an ongoing, growing routine; especially at the WTA level. How can one not predict such an up-and-down cycle in the rankings given the convergence of existing athletic powers (Swiatek, Rybakina, Sabalenka, etc.) and the current young and talented players? One player 'owning' the season, like Iga did in recent history, may be a thing of the past.
May be, as you said but Swiatek might have turned a mental corner though in that cliffhanger against Collins. Her mental state didn't follow the scoreline as it should have. But only just and because the American fell flat a bit. Like Parry against Mirra. But to come back on topic, i still think it's in Swiatek's and Sabalenka hands with only one real threat.. Coco Gauff. And a Rybakina in the zone. Anisimova? Noskova? Timofeeva? Others? It's all possible but not this season. So, we might need to wait until Andreeva hits balls 10 miles an hour faster..