You may feel annoyed when your mother-in-law interferes with your child's education. This kind of trouble is not only because of interference (denial) and anxiety in children's growth, but also because of losing authority in front of children (commonly known as losing face).
Personal suggestions: First, get rid of prejudice and keep an objective attitude towards mother-in-law's educational views. The older generation does spoil their children sometimes, but it can't be said that all their educational ideas have problems. Calm down and communicate with them. We will adopt what she said is right and communicate with her calmly.
Second, show your attitude, including your understanding of your mother-in-law. Parents are the main responsible persons for education. There is no doubt that mother-in-law loves children. Isn't it a good thing that one more person in the world cares about your children? Express to your mother-in-law that you know her love for your children and thank her for her dedication to your family (be sincere). At the same time, emphasize your own educational ideas, and discuss what to do when there is a conflict in educational ideas (tips, guide your mother-in-law to say it herself, and finally choose a method acceptable to both of you). For example, even if there are conceptual conflicts, when you educate your children, your mother-in-law will temporarily avoid it, and then discuss whether this educational method is correct afterwards.
Third, a passage from the Tao Te Ching is attached: "We are new, we have less, and we are confused." The expression and content can be expressed tactfully, and it is easy to fold if you use too much force. Two people are often in a lose-lose situation, so it is better to learn the elasticity of water, drop water wears away the stone and slowly penetrate into her.
Ps: You still have your husband as an important weapon. You should use him as a blending agent.