Doctor Who fans love to categorise Doctor Who stories and one of the most often discussed ‘genres’ is the ‘pure historical’.
A feature of the TV series during Seasons 1-4 but then quietly retired, they saw the Doctor, his companions and the TARDIS be the only ‘anachronistic’ elements within the story. They would also often feature historical figures and see the Doctor and his companions having to survive turbulent periods of history.
Many fans call for their return to TV and whilst that may seem a bit of a pipe dream, the expanded Whoniverse hasn’t been shy in returning to the genre.
I stumbled upon The Behemoth on a whim when I was first dipping my feet into Flip and Constance. As it turned out, it got me effectively hooked on those two companions. There was some iffy-ness regarding the slave trade aspect, but overall I enjoyed this audio. Generally speaking, I prefer stories that aren’t too heavy on the sci-fi elements. The Marian Conspiracy is another good one, as OP mentioned.
I used the TARDIS Wiki as a source… looks like whoever made the list I saw didn’t know as much as you! Thanks, I’ll add them.
But going back to the subject of your post - I’m not a huge fan of pure historicals. I’m willing to be proved wrong when I listen to The Marian Conspiracy, but I like Doctor Who because of the sci-fi and aliens mostly!