Thanks for checking back in! I'm interested if we could solve this issue, as I haven't heard of this yet, outside of your feedback post.
On both Windows and Linux, the game for most players seems to only use a little under 800 MB of RAM on the main menu. and a little under 900 MB in game, as well as when returning to main menu after playing a bit.
If you're not available to work through this, that's absolutely okay, but if there's anyone else with inflated RAM usage who is up for it, I'd appreciate it if we looked through together.