Collection2Preset is a program that turns a Collection into a GMOD preset. Ensure that when loading it you use "Install add-ons that are no longer present" to ensure no add-ons are left uninstalled!
Step 1: Put the EXE anywhere on your computer
Step 2: Run it
Step 3: Enter the Collection ID you want to turn into a GMOD preset
Step 4: If prompted, rename the new preset or overwrite the existing preset
Step 5: If a problem occurs, use the generated presetsbackup.txt file. Ensure you delete old ones to avoid cluttering them!
You can download the code to use and modify if you want, but the recommended option is the EXE, as it bundles all requirements and is easy to use.
At the moment this program is WINDOWS ONLY, I do not have the testing environment nor the time to make a MacOS version