Reminds me of other Electron-based editors, most notably Atom (which I abandoned as a Markdown editor just for that reason).
Tested your file on Linux (Mint), editing is quite ok but preview unbearably slow (especially notable when linked so you can see what you do).
And of course this will get worse the more plugins and/or CSS snippets one uses. It pays to stick with the bare minimum required for one’s work.
I hope Obsidian will stay/get as performant as possible (given the technology used), because its features are so much worth it.