Oh my goodness, it's so bad it's just beyond the joke it was surely written to be. No one could possibly have done the slightest bit of research so I must conclude it's a prank to make the BBC commissioning producer look like a total fool.
The script is silly, the plot is silly, the back-story is just annoying time-filling, the set and props are rubbish (with the honorary exception of the torpedo room) but at least some of the actors are trying.
Oh well, at least the BBC woke demographics are all adequately ticked off.