Welcome to the User Community Forum @pohimmgoh!
As you have already found out, there is no monitoring without the Noonlight Monitoring HMS Subscription, which is limited to the domestic United States. It is that subscription license that activates the features in the Monitoring tab, to include the use of the keypad.
If you would like to see a self-monitored feature developed for the Sense Hub (either with or without a subscription), follow this Wishlist link and vote for the feature at the top. Add your detailed post at the bottom of you feel inclined.
I believe the limitations to professional monitoring outside of the United States are because of the specific infrastructure required for proper police dispatching. There are many legal and procedural factors that would cause problems for Noonlight, with a focus on domestic U.S. monitoring, to activate an emergency response internationally. It would require a massive expansion in the existing Wyze partnership landscape.
If you would like to see this expansion to include international monitoring subscription service, you can follow the link to this Wishlist topic, vote for it, and add your post at the bottom.