Arthurian novel with sci-fi tropes

Question

I am looking for a book which was a variation of Arthurian legends. I have read it in Polish around 10 years ago, but I'm quite sure book was translated (probably from English).

The story was set up in the medieval times. The main clue I remember is a cave with some sort of futuristic equipment and silos capable of hibernating(?) people. I think book started when Merlin woke from his long sleep to fulfill his quest of guiding Arthur (it may be that Merlin woke Arthur from the silo, but I am certain about someone waking up). Then Arthur goes on his quest and at some point meets Morgan. I recollect her playing some mind tricks on Arthur and this part was vague, but I can't say if it is due to my hollow memory, lack of understanding of written words, or indeed vagueness.

I know it's not much, but I've seen some impressive identifications here, so I have hope.

I have checked this list, but did not find any description mentioning fantasy setting with sci-fi elements.

Answer 1

Could this be Merlin's Mirror by Andre Norton?

In this great science fiction novel, Andre Norton brings to new life the legendary King Arthur and the wizard Merlin in the light of modern knowledge of a lost period of history and today’s understanding of science and interplanetary communication. Yet, as in all Norton’s wonder novels, this is a fabulous adventure in fantasy. Here is Merlin, half star-born, gifted with the advice of an alien intelligence, given the task of renewing civilization and starting humanity again up the ladder to the stars. Here is Arthur, unaware of his stellar heritage. And here too, is the Lady of the Lake, akin to Merlin in that she is also a listener to the music of the spheres and obedient to a celestial command post.

Found with a search for arthur merlin "cryogenic" (the quotes force the term to be included).

This review is the one that mentions cryogenic storage, namely that at one point, Merlin is kept in it, which results in him emerging many years later unaging for a time. I found an ebook copy and scanned through the beginning. It does not start with someone waking up in a hibernation silo, but rather of an alien probe awakening to ensure Merlin's conception.