Hi,

To change the text on the button, you need to extend the actual XML template of the button

1. First you need to locate the actual template from the addons
2. Inherit the template in your custom module
3. Replace the text of the button.
4. Run the module

Please refer to the below blog to get an idea of the inheritance of the XML Template

https://www.cybrosys.com/blog/an-overview-of-template-inheritance-in-odoo-16

Hope it helps,