Error message after call of menuController.open() on ion-menu: "ASSERT: can not be animating"

1. The argument taken by menu.open() is a boolean value whether or not the menu animates. Not the ID of the menu Ion Menu docs

2. I am not a vue expert but I think you want to make a template ref in that ion-menu (ref="myMenu"), then, target that in your onMounted() with await this.$refs.myMenu.open()

Let me know if that is right!