Not sure if I can do anything about that, because they are rendered in two separate events.

maybe floating the whole block once a boss event is detected?

I'm pretty sure that the boss overlay can be completely customized, allowing you to make it taller. I'll have to check what exactly the boss info event allows you to do.

Or just add blank lines.
.... ....<line>
.... .... ....<str> </str>
.... ....</line>

that's now responsive tho