I say this affects the version 1.14.1 so i can post this but as a warning im going to tell you it is all the way back in 1.13 and makes that version and all future versions unplayable. I have 1 gigabyte allocated because i use so much memory for other tasks, and minecraft uses over 35% of that to launch and over 55% of that to load a minecraft world when you say there are no problems with lag you've seen nothing. 99 or 98% of allocated memory for minecraft is used at all times and 0 fps constant. and minecraft rthinks only half the allocated ammount is allocated because all that is used the moment it launches. my computer can easily handle earlier versions but your choice to load everything at once is terrible. even with your optimizations i still cant load 1.14. and i want to see your new map but it doesnt even work in 1.13 you use a different world format so i cant. the version is still too laggy but much faster i havnt tried it though. the only version i can use is the outdated 1.12.2 and the map doesnt work there, also it was a stupid move making the map for 1.14 because of the lag and earlier and i hate this i am mad fix this before 1.20 or im quitting!!!!
It was changed to 2GB for a reason...