That's personal choice. I've got 2tb sn850 nvme and corsair vengeance RGB 32gb 3600C18. I wanted the higher storage and the ram was a lot cheaper at the time then the crucial(out of stock at the time and the Group8 Sammy stuff which was closer to £300.. Or another sammy b die.. Remember another forumm member buying somw when i was looking) .
If i had to do it now, doubt id change much.. Maybe gone for the sammy b die 2x16gb 3600c16 while it was on offer at £179.. 32gb more than i need but my laptop was brilliant when i first hot it, now its a stuttering mess. Id rather have too much than too little.
As to 4x8 or 2x16...gamernexus did a test on 2x8 v 4x8...4x8 was faster, but then said 2x16 was better than 4x8...i also wanted the ability to get more ram if i so desired... 4x8 would mean replacing all my ram, 2x16 means i have 2 spare slots to get more.
Which is better, 4x8 or 2x16 also can depend on mobo and the configuration of rm slots.
At end of day, my setup is a monumental uplift to what ive been using... It fast for me, getting high fps in games.. If i left a couplr for going c18 ratger than c16, i wouldn't notice