How "fluid" is swimming?

So I'm a middle-aged guy who took up swimming a few years ago--and loves it! Not a great swimmer, but a person who has pretty solid mechanics in three sports. So here's my prologue, then my question. Some actions are fluid: running, shooting a layup with normal elevation. By fluid, I mean you transfer the energy forward in a continuous motion without "cocking" or "setting up" the next stride, or the upward motion off the court. Other actions we may call "fluid," but they are not: high jumping, a tennis serve, swinging a golf club. In all these, there is a hesitation (very slight) while one gathers so that energy can be properly delivered to the key motion. A tennis serve should be smooth, but if there's not that instant when you are setting yourself up for the explosive movement, then it will never be a powerful serve. So which is swimming? Specifically, the reach in freestyle? I know you are not supposed to have a "dead spot" in your stroke, but is the idea a continual forward rolling motion, or does one stay relaxed, yet **** a bit, or set up each reach? Is it a flywheel, or is it a smooth, relaxed succession of spear thrusts with a little torque behind them? Not sure that it matters, but in my case I'm asking as someone who has (or at least tries to have) more of a hip driven stroke. I've had a little coaching and have read a lot of stuff, but I can't say I know the answer. Thanks for considering this!