Create themable field group
The field group module is designed to solve this exact problem The Drupal 8 version is reasonably up-to-date.


  Fieldgroup will, as the name implies, group fields together. All
  fieldable entities will have the possibility to add groups to wrap
  their fields together. Fieldgroup comes with default HTML wrappers
  like vertical tabs, horizontal tabs, accordions, fieldsets or div
  wrappers.
  
  https://www.drupal.org/project/field_group