You can also play around with the settings like Settings > Editor > Strict line breaks, or consider whether you can add two space characters at the end of the lines in a verse to make the line shift happen. Both of these are less obtrusive compared to having to insert <br> in all the poetry.
Another simplistic solution, if the line breaks are already in there is to enclose the entire text in a code block, and then use CSS to change the font to something more likeable. That should preserve the line breaks, and possibly allow for you to add some formatting to the single lines in question. (In other words, first change the text into pure code display, and then reformat into nice looking text again. This can be done using cssclasses on the files in question, so that you don’t mess with every code block all across your vault)