Short answer - you can't really, beyond doing exactly what you suggested, or using PDF lyrics so you can use multiple fonts, embed graphics, etc.
This is why I raised this feature request - https://support.stagetraxx.com/d/3652-feature-req-ability-to-use-multiple-fonts-in-the-lyric-sheet
By default, ST is using a variable-width font. It's very much the norm in apps and documents and what we are used to. But it's a nightmare for tablature where you really need a fixed-width font so that, as in your case, hyphens (along with the other characters) retain a fixed width as opposed to being randomly joined.
You can change ST to fixed-width font in Settings, but this is a global all or nothing setting. So ALL your lyrics will change to using fixed-width which will look like they have come out of a typewriter or 70s teletext... but your tab will be great 🙂
