odoo-product-addons/product_variant_price_choice/views/product_views.xml

<?xml version="1.0" encoding="UTF-8"?>
<odoo>

  <record id="product_template_only_form_view" model="ir.ui.view">
    <field name="name">product.template.form.inherited</field>
    <field name="model">product.template</field>
    <field name="inherit_id" ref="product.product_template_only_form_view" />
    <field name="arch" type="xml">
      <button name="action_open_attribute_values" position="attributes">
        <attribute name="attrs">{'invisible': [
          '|',('parent.fix_variant_prices', '=', True),
          '|', ('parent.attribute_line_ids', '&lt;=', 0), ('parent.is_product_variant', '=', True),
          ]}</attribute>
      </button>
      <xpath expr="//page/field[@name='attribute_line_ids']" position="before">
        <group class="o_label_nowrap">
          <field name="fix_variant_prices" />
        </group>
      </xpath>
      <!-- <xpath expr="//field[@name='list_price']" position="attributes">
        <attribute name="attrs">{'invisible': [
          ('fix_variant_prices', '=', True),
          ('product_variant_count', '&gt;', 1)
          ]}</attribute>
      </xpath> -->
    </field>
  </record>

  <record id="product_normal_form_view_default_check" model="ir.ui.view">
    <field name="model">product.product</field>
    <field name="inherit_id" ref="product.product_normal_form_view" />
    <field name="arch" type="xml">
      <xpath expr="//field[@name='uom_id']" position="after">
        <field name="fix_variant_prices" invisible="1" />
        <field
          name="fix_price"
          attrs="{'invisible': ['|',('fix_variant_prices','=',False),('product_variant_count', '=', 1)]}"
        />
      </xpath>
    </field>
  </record>

  <record id="product_variant_easy_edit_price_view" model="ir.ui.view">
    <field name="model">product.product</field>
    <field name="inherit_id" ref="product.product_variant_easy_edit_view" />
    <field name="arch" type="xml">
      <xpath expr="//label[@for='standard_price']" position="before">
        <field name="fix_variant_prices" invisible="1" />
        <field
          name="fix_price"
          attrs="{'invisible': ['|',('fix_variant_prices','=',False),('product_variant_count', '=', 1)]}"
          widget='monetary'
          options="{'currency_field': 'currency_id', 'field_digits': True}"
        />
      </xpath>
    </field>
  </record>

</odoo>