How much RAM is actually needed?

I am currently 650h in and trying to use all Pure Nodes worldwide in this run. As you may imaging the factories are big and distributed. It is going well.

Sadly, yesterday I noticed that the game is now running at 40 fps with some lagging here and there. Changing the video quality parameters didn't change the fps count (ultra to low). Starting a fresh run gives me 200fps with the same settings.

I read that 16GB of RAM should be enough, with 8 being minimum, but I am starting to think that I need 32GB? What is your experience?

EDIT 1: GPU (RX 6800) is at 65%, CPU (5600X) is at 70%, RAM (2x8GB DDR4 3200MHz) is at 83% Screenshots of System while playing: https://imgur.com/a/V5JeIY7

EDIT 2: Changed BIOS RAM speed from Auto to 3200MHz. Now I am getting 50FPS instead of 30FPS. Thank you for the idea u/klyith

EDIT 3: HWInfo claims that RAM usage goes to 99% while loading the save file and back to 80% afterwards. Might be a sign of object juggling due to missing memory space?