In the vue3 project, the ts writing error reporting component is not exported by default, because Vetur-v0.35.0 does not support the vue3 version, you need to download Vue Language Features (Volar)-v0.29.8
<template>
<MyHeader></MyHeader>
</template>
<script setup lang="ts">
import MyHeader from "../components/MyHeader.vue";
</script>