A:Answer UPDATE / CORRECTION TO MY ANSWER A MONTH AGO.
I have now opened up my new LG 17 and include pictures.
There are two slots for NVMe drives and both are occupied, but you could switch one out.
Sorry, I was wrong...the memory is soldered to the board. No upgrades on that.
New pictures of inside of the PC. Caution: you have to pull off rubber feet and screw covers that are EASY to loose.