You don't want to look like a bodybuilder.
You just want to be in great shape.
If you exercise one muscle per day, you can spend all your willpower on that one muscle.
It takes willpower to let that muscle burn, and our willpower is not unlimited.
So you better spend that limited amount of willpower wisely.
Spending all of it on one muscle, you can truly push it. You can let it burn.
No pain, no gain, so they say. And that is the truth. The pain is caused by the accumulation of lactic acid, which hurts your muscle. That damage stimulates muscle growth. More burn means more damage, means more growth.
There is only so much pain that you can handle. And that is why exercising only 10 minutes per day is most efficient; maximum return for your investment.

Secondly, it does not make sense to build a beautiful body and lose it some years later.
If you want a beautiful body, you want that body for the rest of your life. Not just for a few years.
So, you need a routine that you can maintain for the rest of your life.
A routine that is doable, for ever.

So, one muscle per day, for 10 minutes, with maximal burn.
For ever.

So, how does that work, exactly?

If you use very heavy weights, you cannot continue doing repetitions for more than 30 seconds. In those 30 seconds, you have almost solely used free ATP (adenosine triphosphate) and CP (creatine phosphate). This lost ATP and CP is replensihed after exercise.
If the weights you are using allow you to continue doing reps beyond 90 seconds (1.5 minutes), up to about 3 minutes, you will mainly rely on anaerobic glycolysis, which results in the accumulation of lactic acid. That lactic acid needs to be removed after exercise (and during light exercise).
If you use even lighter weights, which allowes you to continue beyond 3 minutes, the increased share of aerobic utilization of glucose and fats (which does not yield lactic acid) will allow for the clearance of lactic acid yielded by anaerobic glycolysis (which here accounts for a smaller share of total energy supply).

So, for each exercise, you need to find weights that allow you to continue doing reps beyond 1.5 minutes, but for 3 minutes maximally. That does not mean you should stop at 3 minutes. It means that you should not be able to make it to 3 minutes. You need to break down before that.
Then, after a second or 2, you start again.
If you repeat that a few times, you will not even be able to make it to 10 minutes.
Then you are done for the day.

So, when you first start doing this, you need one timer for the 90 seconds, and one for the 3 minutes.
After a while, you know exactly which weights/resistance to use.