As seen below the property "something" does not get suggested on the OptionsAPIComponent.
Also no reported error on either even though they're missing the required property.

To reproduce, use below code. I set up a project with npm create vue and no to everything except eslint+prettier, then add the components.

<script>
import OptionsAPIComponent from './OptionsAPIComponent.vue'
import CompositionAPIComponent from './CompositionAPIComponent.vue'
export default {
  components: {
    OptionsAPIComponent,
    CompositionAPIComponent
  }
}
</script>
<template>
  <OptionsAPIComponent />
  <CompositionAPIComponent />
</template>

<template>
  <div>{{ something }}</div>
</template>
<script>
export default {
  props: {
    something: {
      type: String,
      required: true
    }
  }
}
</script>

<script setup>
defineProps({
  something: {
    type: String,
    required: true
  }
})
</script>
<template>
  <div>{{ something }}</div>
</template>

Property is not suggested externally on component reference

Property is not suggested internally in template

Property is not suggested on component instance

Method is not suggested on component instance

After adding data() to the component resolves a lot of LSP issues

But not reference to internal properties

Properties are correctly suggested under the $props property (when data() is specified)