I've discovered that I really enjoy the idea of protagonists with contemporary/futuristic knowledge going to primitive places and uplifting their knowledge of tech/tactics. The tech base upgrade makes for entertaining analogue to a training montage. Also known as Stranded with Edison (https://tvtropes.org/pmwiki/pmwiki.php/Main/StrandedWithEdison), as a trope.
Lots of examples of it in sci-fi, the Empire of Man series did it very well, it's the foundation of the Destroyermen series, 1632 is another one (shame that's kind of stalled).
There aren't a lot of books on the tropes page, though. What other examples have people come across that are worth checking out? Bonus points if it isn't woke (with they/them characters shoehorned into the place).
It's a pretty major theme in A Fire Upon the Deep. Which also happens to be a great book in general and not in any way wokey.
Robinson Crusoe in 1719 was probably the first of the big castaway novels. It was a megahit, and was followed by other castaway novels such as The Swiss Family Robinson in 1812.
Jules Verne trued his hand at the genre with The Mysterious Island in 1874-1875, and the result is very much in the flavor of an Edisonade. Verne is basically trying to one-up the previous novels by having his characters completely rebuild civilization over the course of the novel, to the point that they have an entire railway system built before they bother building a ship to go home in. I wouldn't say it was as good of a book as Robinson Crusoe or Swiss Family Robinson, though. It's just not as grounded, and depends on too many convenient gifts from the author.
The Martian by Andy Weir is a modern version of the genre.
Also, check out the Wikipedia entry for Robinsonade:
https://en.wikipedia.org/wiki/Robinsonade
The only one in that genre I ever read was Lest Darkness Fall by L. Sprague DeCamp, and you doubtless already know about that one. It was pretty good. A 20th Century man goes back in time to the latter days of the Roman Empire and tries to use his modern knowledge to prevent the collapse of the empire. He doesn't so much do it by military tech, but rather by things like telegraphy and even double-entry bookkeeping.