Customizing how the HTML is output (instead of CSS acrobatics)

Hello. Like most modern websites, we use a styling framework with grid, flex etc. This requires that we show forms in sensible ways with code like this:

  <div class="grid"> 
     <div class="col1">LABEL HERE</div>
     <div class="col2">INPUT FIELD HERE</div>
  </div>

However, as seen in articles like these, Contact Form only forces its own HTML and requires us to do CSS styling. TO achieve sensible structures like left/right input boxes, we need to do all manner of float directives, which is hard to make responsive.

Any pointers on how we could embed our own HTML in the contact form? Thanks.