Gimp 3.0.6 on Windows 10 22H2 on Intel core i5 4460 with 16GB RAM and internal SATA drive. Opening a simple JPG musical score image takes 21 seconds. Hangs on export after working on it for an hour copying and moving musical notes around to correct errors. Moved to Gimp 2.10.18 on Linux Mint on Intel Core i3 2120 8BG RAM and internal SATA drive. Opening the same file was instantaneous, worked fine, export was almost instantaneous. This is not a demanding task - what is going on? Are there command line options for logging for collecting data on this?
No options needed just start gimp from the command line. It should output to that terminal what is happening… You might need to confirm the name of the exe for gimp just to make sure. (gimp.exe should work) but i’ve not used windows in at home in over 25 years so take that instruction lightly. 
Use this command.
“C:\Program Files\GIMP 3\bin\gimp.exe” --verbose
Welcome to the forum. I have nothing worthwhile to add here except nice ad for Linux Mint vs Windows 
. I too have been impressed with the speed of linux mint on old machines I have. I hope knowledgeable people can help you with your issue.