Why not represent them as PlantUML or Mermaid and render to HTML/CSS? That way you get far superior layout capabilities, particularly for text, than SVG or canvas provide you.
You can embed HTML in SVG, vice versa and use CSS on both.
In fact one little trick if you are doing a complex animated layout with SVG is to nest HTML elements with it that you animate it via CSS transitions or keyframes, which are much more optimized than SVG animations in browsers.
In fact one little trick if you are doing a complex animated layout with SVG is to nest HTML elements with it that you animate it via CSS transitions or keyframes, which are much more optimized than SVG animations in browsers.