By learning more than one swimming stroke, figure out which one is more manageable for you. Try learning multiple strokes simultaneously. How else would you find out which stroke is more effortless for you?!
Besides that, you improve the other strokes automatically by trying to learn multiple strokes at the same time. You are developing breaststroke by improving your freestyle and or backstroke.
You will be using similar muscle groups while swimming. Even though motion mechanics differentiate from stroke to stroke, they focus on the same goals.
All swimming strokes aim to propel you through the water by creating resistance with the help of your arms and legs. All four strokes help your body stay close to the surface if you do them correctly.
Besides that, swimming one stroke could get dull. Imagine focusing on learning how to prepare only one dish that you love. At some point, it will be delicious. However, you will miss out on trying other delicious meals.
Using this method, I have helped many adult beginner swimmers
gain more confidence in the water. Try it out yourself and figure out which stroke works better for you.