Children's art training is close to preschool education, which is not professional, but relatively easy. Getting along with children is also an art. I don't know if you have the talent in this field, otherwise you will be unhappy and depressed.
Wall painting is a single business, and there is little after-sales service after it is finished. As long as the painting is not too bad and outrageous, there will basically be no big controversy. Children's art is relatively complicated. Children's learning ability and understanding ability are the reasons that affect your teaching performance. It's hard to meet unreasonable parents' meeting again.
Alas! In short, all walks of life have their own hardships. Considering your own conditions and specialties, it is right to do what suits you best. Be happy, it doesn't matter if you earn less money. However, if it is only to increase income, I think children's art education has more development and prospects.
I hope it helps you.