Why not go along with scientists as they explore and survey the deep looking to understand these habitats? Schmidt Ocean livestreams their entire ROV dives (7 hour long livestreams or so usually). It is a blast to watch along or just put in the background as ambiance and not only are they frequently diving but they have an archive of 600 or so dives up on YouTube so you aren’t going to run out of 1000 leagues under the sea content anytime soon (this ROV can do 4500m under the sea).
Usually a scientist is tasked with explaining to the stream what they are seeing and doing and it is super fun to just be a fly on the wall in the control room of the ROV ship. A lot of marine science institutions with submersibles will put out short educational content or highlight reels but it is just so much more compelling to sit along for the ride, through the mundane and extraordinary as scientists visit a place on earth humans have never seen.
Also the ROV camera is extremely high quality with a great zoom, grainy footage this is NOT.