HI there
Is there any plan for the WebClipper on Microsofe Edge add-on store?
You can actually install it from the Chrome store
yes, but Some enterprise enviroment doesn't allowed install from Chrome store.
The thing is that it's costly and very time consuming for us to support stores, so we only support those that are absolutely necessary.
If a company is interested in having it in the Edge Store, they can perhaps either provide assistance (have one of their employee maintain it, with our help) or sponsor us? We can be contacted here on the forum, or by email.
I also doubt that many enterprise environments would allow you to install Joplin in the first place.
Well, that's what JoplinPortable is for (if it's a Windows PC). IMO the portable version is one of the great advantages of Joplin's multi-platform approach.
It is great, but also blocked on my enterprise laptop. 
I see – strict blocking policies, I must say. Which means there's only one kind of software that is truly portable: a web app running in any browser. That's why services like Google Keep are popular, although they don't respect users' privacy.
Would something like 'Proton Notes' with E2EE be possible? It would probably run into the same difficulties as Boxcryptor and Cryptomator: privacy ensured, but server-side search disabled, which is bad for handling document files in the cloud and even worse for storing notes.
That's probably the reason why there'll never be a proper web app for Joplin, I'm afraid.