Yes, that is pretty much how WeChat works. It is mostly a glorified messenger and payment system (like current whatsapp), that they added a proprietary webbrowser with addons and storefronts on top (and wechat gets commission from said webpages and addons people access through them).
You could maybe get a similar experience in Android if you install Firefox, save a bunch of commercial websites as favorites, save another bunch of social media websites as favorites, add whatever addons there are (ublock origin for the win), and access stuff only through it.
Voilá, now you have an everything app.
You have root access in pixel phone and can install custom ROMs like graphene OS.