You can create server action through XML as below:
Actions — Odoo 14.0 documentation
<record id="act_hr_employee_holiday_request" model="ir.actions.server">
    <field name="name">Time off Analysis</field>
    <field name="model_id" ref="hr_holidays.model_hr_leave_report"/>
    <field name="binding_model_id" ref="hr.model_hr_employee"/>
    <field name="state">code</field>
    <field name="groups_id" eval="[(4, ref('base.group_user'))]"/>
    <field name="code">
    action = model.action_time_off_analysis()
    </field>
</record>
    
You can create scheduled action through xml as below:
 <record id="autovacuum_job" model="ir.cron">
    <field name="name">Base: Auto-vacuum internal data</field>
    <field name="model_id" ref="model_ir_autovacuum"/>
    <field name="state">code</field>
    <field name="code">model._run_vacuum_cleaner()</field>
    <field name='interval_number'>1</field>
    <field name='interval_type'>days</field>
    <field name="numbercall">-1</field>
</record>
How to Create Scheduled Actions in Odoo – Ngasturi Notes