Instead of the focus on the instruments, could there be a focus on what the children should be taught to learn the cultural and social value of music, as well as helping those children who want to be able to choose a life in the entertainment industries as they get older?
Melodica, Ukulele, Recorder, Percussion instruments, they all have an aspect of music appreciation and culture that can be used to help the children learn. Keyboards, wind and strings.
Obviously teachers have to battle with real physical issues like cost and safety from germs. So it is not easy we should be helping the teachers.
Also maybe if adults were not so critical or sensitive to the noise the children make while learning, it would be easier for the children and the teachers? How hard is it to smile and enjoy watching a child have some musical fun, even if the noise is not perfect? In most cases there is a noisy learning period for every human who starts to learn a musical instrument, children are not really able to get away and learn where they don't annoy others with the noise, and it can be unhealthy if they do, so why not start to cultivate an attitude of acceptance and try to enjoy the noise and share the excitement of learning for the children?