They still line up (when rendered with correct double-width), the east-asian characters just take up two “slots”, as if they were two normal characters. I don’t know if you see a problem with that, or if you’re talking about renderers and/or applications that don’t correctly handle this double-width logic.
My point is that if handled correctly, e.g. in terminals, there is no problem with that, as long as the application is double-width aware. For example I use Mutt as a mail reader in a terminal, with Vim as an editor, and mixed latin and east-asian characters work fine with them and line up on the terminal grid.
I don't think I've ever seen a double-width font outside of an actual terminal emulator though. It's really frustrating that the fonts used by all IDE's and graphical emacs/gvim/vcode seems have this mixed script spacing issue.
My point is that if handled correctly, e.g. in terminals, there is no problem with that, as long as the application is double-width aware. For example I use Mutt as a mail reader in a terminal, with Vim as an editor, and mixed latin and east-asian characters work fine with them and line up on the terminal grid.