In Drupal 7 there was the start of Per-Bundle Storage (PBS) to try to store field data in a single database table if that made sense and was possible given the nature of the field. The PBS for Drupal 7 module didn't ever become very popular, though and was not ported to Drupal 8.
I understand it's possible to write custom Entity code for Drupal 8 to store data in a single table if you want (e.g. the
User entity stores it's fields in users_field_data).
I'm curious if there's an easy solution I've overlooked to store several fields in a single database table.