Let me have all my notifications, please

While I appreciate that Apple has allowed an option at all to use the more affordable smart watch options with our iPhone, I dont understand the lack of third party support notifications. Facebook messenger is a program found in iTunes Store, so its cleared for use with iPhone...why cant it relay notifications to my zen watch 2? It does to my Martian notifier watch without problem, but new zen watch sees texts and some emails (only gmail not other addresses in iPhone mail) but no Messenger. What gives, Apple? If the Apple Watch was less expensive and had a low power always-on watch option, I would get one. But its not right for me...loosen the reigns on notifications from programs you already let us download. Please

MWats1 about Wear OS by Google