I host my own Lemmy and Mastodon instances. It's hard to say what I actually pay because I use the server for a lot of things but I guess the monthly price per user is about 1$ or less. The bigger instances are of course more expensive. That is why it is important to spread out communities across instances.
I am not a 100% sure I understand your setup but it shouldn't be possible to add a Kernel module in a container. The container uses the Kernel of the host and doesn't have a Kernel on its own.
Well you see in winter there is snow, and in the summer there is heat and in fall there are leaves on the rails and in spring there is pollen and the seasons are always so surprising. How are they supposed to handle that?!?!?
Pixelfed and Mastodon have a comparable presentation. Lemmy is a bit different. The focus is different. It might be possible to display content from every fediverse implementation but it might be a less than ideal experience for many of them.
The problem is that it will take ages for them to get any adoption in a new browser. Firefox used to be a big player and then chrome came along. Now most of the people don't even try Firefox anymore. I still hear a lot of "Firefox is slow" sentiment even though it isn't.
The problem isn't Edge in itself. It is good if there are many browsers. But when Javascript became more than just a play thing, all of a sudden browser slowly moved to chromium as an engine. There used to be Opera, IE, Edge, Firefox, Safari and Chrome with each their own browser engine. Now there is only Chromium/Blink, Safari and Firefox left. Google is way too powerful with their marketshare. They constantly try to implement features that are bad for users.