Minecraft.Windows.exe Memory increases gradually and game becomes unplayable after about 5-10 minutes.
I have 16Gb Ram. I have tried with Windows Game Mode On/Off. Even when doing nothing the memory continually increases. When a friend joins from the LAN it becomes worse.
This was using the Winding River seed.
Screenshot 2020-07-05.1.png - shows 4GB after ~1minute.
Screenshot 2020-07-05.4.png - shows 11GB after ~8 minutes with only 1 player, with 2 players via the LAN / Friends tab it uses memory a bit faster.