Hi Kevin, I think this feel you described is quite normal for many players that it feels more comfortable to hit flatter during the rally and that you can prepare and play this type of shot quicker than a topspin shot. I would say you do generally want to be playing more of a topspin stroke during the rallies however as this gives more safety to your shots and control in the long run. It is a different type of topspin shot compared to when playing against backspin though, as you described loading up and it taking more time, this is definitely the case when playing backspin but shouldn’t be so much when in a rally.
so the topspin shots you play against a block or in a quick exchange you don’;t need to drop the bat and you can shorten the stroke down, so just focusing more on brushing over the top of the ball and having a good flex in the elbow and quick body rotation. Having a nice short snappy topspin in the rallies will help in the long term and hitting flat when you need to or the ball is much higher. This will take a bit of time getting used to but will help and adds another element to your game 🙂