Hi,

You can create an option for cancelling by creating a custom module using below code

in .xml

<record id="view_sale_order_tree_button_inherit" model="ir.ui.view">

    <field name="name">sale.order.tree.button.inherit</field>

    <field name="model">sale.order</field>

    <field name="inherit_id" ref="sale.view_quotation_tree_with_onboarding"/>

    <field name="arch" type="xml">

        <xpath expr="//tree" position="inside">

            <header>

                <button name="multiple_sale_order_cancel" type="object" string="Cancel Order"

                        class="btn btn-primary d-inline-flex align-items-center pl-0 px-lg-2 py-0 mb-0 ml-2"/>

            </header>

        </xpath>

    </field>

</record>

in .py

def multiple_sale_order_cancel(self):
    for rec in self:
        rec.action_cancel()

By adding this accordingly the cancel button will be visible in the model tree view.
this is also applicable for other models and other functionalities like mass confirmation, etc. but should care for the function name that wrote inside the python function.
Don't forget to add the python files in the __init__.py and the XML files in the __manifest__.py obviously.

Regards

The below free module allows you to cancel multiple sale orders. it's available for Odoo 14, 13, 12. If you are using another version, you need to upgrade it if needed.

Cancel Multiple Sale Orders | Odoo Apps Store