With 16GB of RAM, the game will runaway with active RAM use as it has unreasonable RAM usage in practice. As mentioned before I have 64GB of RAM, and the game will use 18GB+ of RAM all on its own. That's not because "if you have more RAM, a game will use more RAM" like some seem to think, this is an issue with this game specifically. No other game uses more than say 6GB of RAM. You know something is up when the game you are playing uses more system RAM than VRAM when no other game has this quirk.
32GB of RAM is the minimum for this game when using any reasonable resolution and GFX settings. When you also factor in system RAM usage by the OS and background apps etc, you are basically left with no RAM left for normal running of the game and OS and disk paging has to be done which will result in performance degrade, even if the pagefile is on an SSD.
If it was at 4K with Ultra and stuff then sure this could be acceptable, but it happens at any res with Hogwarts. It's poorly optimised for resource usage.