Hi,
I found that you also have post another case.
You can modify PagedPollSize value at regedit to increase the size or PoolUsageMaximun to set a lower % were the memory manager start the trimming process earlier.
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Memory Management.
PoolUsageMaximum (REG_DWORD) : value at which the Memory Manager starts trimming the pool. Default is 80, but you can set it to 60 or even 40.
PagedPoolSize (REG_DWORD) : setting the value to 0xFFFFFFFF allocates the maximum paged pool.
Also, you can uncheck "Automatically manage paging file size for all drivers" at virtual memory options and increase page file size.
https://www.online-tech-tips.com/computer-tips/how-to-optimize-the-paging-file-in-windows/
Win2012 R2:40.2/45.4GB committed Win2019:19.1/19.4 GB
I consider that something isn't accessing ram correctly or isn't letting it go, either the application has a limit or the way memory is handled in Windows 2019 is affected by something installed. Some information below may explain the memory issue.
https://superuser.com/questions/943175/windows-says-ram-ran-out-while-there-is-still-4-gb-of-physical-memory-available
Hope this helps and please help to accept as Answer if the response is useful.
Best Regards,
Carl