whatsapp_web_groups/custom_project/views/project_task.xml

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

        <record id="custom_project_project_task_form" model="ir.ui.view">
            <field name="name">custom_project_project_task_form</field>
            <field name="model">project.task</field>
            <field name="inherit_id" ref="project_enterprise.project_task_view_form"/>
            <field name="arch" type="xml">
                <xpath expr="//div[@id='date_deadline_and_recurring_task']" position="attributes">
                    <attribute name="invisible">1</attribute>
                </xpath>
                <xpath expr="//label[@for='date_deadline'][1]" position="attributes">
                    <attribute name="invisible">1</attribute>
                </xpath>

                <xpath expr="//label[@for='date_deadline'][2]" position="attributes">
                    <attribute name="invisible">1</attribute>
                </xpath>

                <xpath expr="//field[@name='recurring_task']" position="replace"/>

                <xpath expr="//div[@id='date_deadline_and_recurring_task']" position="after">
                    <label for="x_start_date" string="Fechas planeadas"/>
                    <div id="planned_date_task" class="d-inline-flex w-100">
                        <field name="x_end_date" invisible="1" required="1"/>
                        <field name="x_start_date" required="1" widget="daterange" options="{'end_date_field': 'x_end_date'}"/>
                        <field name="recurring_task" nolabel="1" class="ms-0" style="width: fit-content;" widget="boolean_icon" options="{'icon': 'fa-repeat'}" invisible="not active or parent_id" groups="project.group_project_recurring_tasks"/>
                    </div>

                    <field name="x_days_duration"/>

                </xpath>
                
                <xpath expr="//field[@name='child_ids']/list//field[@name='date_deadline']" position="attributes">
                    <attribute name="column_invisible">1</attribute>
                </xpath>

                <xpath expr="//field[@name='child_ids']/list//field[@name='date_deadline']" position="after">
                    <field name="x_end_date" column_invisible="1" required="1"/>
                    <field name="x_start_date" string="Fechas planeadas" required="1" widget="daterange" options="{'end_date_field': 'x_end_date'}" optional="show"/>
                    <field name="x_days_duration" optional="show"/>
                </xpath>

            </field>
        </record>

    </data>
</odoo>