Hello Hugo,
I will reply here to both this and your similar request in a related thread
Both Microsoft for Edge and Google for Chrome provide official ADMX templates for each version of their browser. The reason you need newer versions is that the set of configuration capabilities changes over time and therefore a new version of the ADMX templates is needed to reflect those changes. You don't *have to* update the templates as often as the browsers update but every time you need to configure something new you will likely need to update the template to gain access to this new capability. In some cases old capabilities are retired and they will be removed from the templates too. For the exact set of capabilities that each browser supports you need to access the official documentation of that browser. The open source Chromium project which both browsers are based of does not provide ADMX templates but such can be generated from the source code if needed.
In your other thread you mention the "default" templates. I presume you mean the one coming with a certain version of the browser. As mentioned above they are good enough as long as the features you need are present in it and still supported by newer versions of the browser.
Regards,
Julian