If you want to learn to play the acoustic guitar you should be working towards being a versatile musician. There are around a dozen alternative ways to finger any open chord that you know. You can buy a chord book or download some chord charts from the internet and then you can experiment with different chord fingerings. Listen to how they sound with other chords. See how they sound as a backing to your singing. Once you start fooling around with chord shapes you will open up a new side to your musicianship, making you a better accompanist and pave the way to your being able to write your own songs.
Practice is important with the acoustic guitar. If you are rusty it shows more readily than with the electric guitar. For your own progress as a guitarist you would benefit by practicing for at least half an hour a day, seven days a week. Aim for that amount, and if you have to because of other commitments, make do with a little less. Regular practice not only keeps your fingers in playing condition but it also trains your ear, even if you do not intentionally work on it. As your ear for music develops you will be more able to pick up new music you hear on the radio, and your ability to improvise will start to grow.
As an acoustic guitar player you can easily carry your instrument around from place to place, so why not practice while you are watching TV or doing something else that leaves your hands free? Muscle memory needs very little attention from the thinking part of the brain once you have your chord shapes memorized. You can practice chord changes on the acoustic guitar just using one hand. Imagine how many times you could go through the changes for a three chord song during the course of a movie. The fact that you are not using both hands does not let you off your obligation to your back and arms, though. You must always practice in a position that does not strain your body.
While we are talking about chords, let us take a look at how you handle bar chords. On the acoustic guitar bar chords require some practice. There are ways of putting off the practice needed to execute bar chords, for instance you could use power chords or simplified chords on the treble strings. Or you could learn bar chords right from the beginning and eliminate all the stress and worry and procrastination involved in delaying something that is, after all, an important part of learning to play the acoustic guitar. So when you learn your basic open chords like E major, G7 and A minor, start to practice the F major chord. This gives you one of the basic chord shapes that can be moved up the fretboard to play more chords. Not only that, the initial effort to learn bar chords can be put in learning the F shape alone. When it comes time for you to move the A major shape up the fretboard, you will find the effort is nowhere near as great.