This is true but in tennis you have a whole lot of technical basis things to learn before you can even dream about being competitive with anyone on a decent level (and with this I mean local club level). Even with great speed and power/strength etc it will take some time to learn to simply keep the ball in play even without any pressure from your opponent, not even talking about slice, volley or a anywhere close to decent serve.But physicality and speed both enable technique and timing to a large extent.
Even the best athlete will hit tons of unforced errors for quite some time. In other sports like 100m or shot put, weightlifting etc, I can see great athletes from other sports being way more competitive even if they haven’t any clue about sports specific technique. For instance there are several footballer who can run 100m in 10.8 seconds or even below which is close to women world record despite never having been trained in sprinting. In tennis there is no athlete from any other sport who - without ever having played - would be anywhere competitive with even a 4.0 let alone a female pro player.