No monospace code blocks?

I'm upset that a meme I tried to remake with Unicode box drawing characters lines up terribly in apps: https://lemmy.ca/post/28490027 Shouldn't code blocks render in monospace?

On Lemmy's web frontend it's perfect:

On Connect it looks like this:

On Jerboa it's basically the same:

Eternity does use monospace but the box drawing characters seem to be too wide.

All I can find about it here is one post from a year ago: https://lemmy.ca/post/1492857