Internet is a finicky thing. What you should be getting depends a lot on what you pay for, what device you have, and the equipment you’re using, not to mention the infrastructure you don’t control. Without more detailed information, it’s hard to say. But, that said, your download and upload speeds are more than enough to do practically anything you should want without much of an issue.
The only two things formatting makdown consistently, for now, are Jerboa and the web interfaces.
I’ve been posting a lot of poetry using some markdown witchery to format, only to realize that some interfaces show all of the markdown even inside the post itself. Jerboa will show it in the summary tile before you click in, but it does format.