Yeah, that doesn't look anywhere near 40% body fat. Weird question, but how much do the implants weigh? Are they more dense than real ones? That could be throwing off the measurement.
Perhaps get a more detailed assessment, maybe something like this:
https://inbodyusa.com/general/what-is-body-composition/
Either way, be careful going too far down the "perfection" path because obviously it can cross the line over to unhealthy. Like I said earlier, especially as you age, it becomes more and more difficult to maintain.
That said, if you really want to continue aging as gracefully as possible, one strategy is to find a competitive fitness activity - I mean one where you are actually participating in competitions - and then train like a competitive athlete does. Of course, if you do this, you're going to
look like an athlete too, which might not be exactly what you want. But you'll also be able to build up your physique in ways that someone who is not an "athlete" can't necessarily do in a healthy way, including extremely low body fat.