The IP68 comments from Samsung and the laser stuff from Google are all liability speak from their respective lawyer teams. You have nothing to lose at this point I suspect and the battery replacement procedure doesn’t even remove the laser elements in question. If you are paranoid about exposure to laser light you can cover the emitter if you need to run open case tests before completing reassembly. Having said that, I think the moderate difficulty level on this is pretty relative. Looks pretty hard to me, especially keeping up with multiple lengths of screws and making sure to put them back in the correct cavities. Good luck sir.