One thing you can do is sort the folder by date [or file size] and just do the files that are the oldest/largest. But yeah, I am sure one of the devs will chime in when the time zone is appropriate. Overwriting the files doesn’t affect the database though, as the file names stay the same [make sure you have that set in JPEGmini!].
I looked at my logs and I did it back in 2021 w/o talking to the devs. But fully get why you would want to make sure first! [my biggest hangup with GS is that text fields loose their focus 100s of times a day, making data entry and typing into them very, very frustrating- that and the “send to Endicia” feature always defaulting to Ground Advantage instead of what the order’s postal class is]. I doubt me reducing the image size has caused either of those issues. 
292GB is quite insane!
I keep app my image dimensions to fit within a 1600x1600 square - but that can be decided before sending to JPEGmini. I always use JPEGmini as my last step. I know JPEGmini has the feature where it can also re-size images, but doing so requires one to export the images to another folder; so I do all my processing beforehand, and use the “optimize originals” [and turn off the warn before replacing files dialog box].
My detailed reply about how I process stuff is at:
EDIT: I should also state: I started using JPEGmini in 2021 [Pro version was for videos, non pro was $39 and just did images; now it is Pro and Pro Suite]. I did not start to resize images until the GS/macOS bug came up a while ago where previews in GS were blurry. While the files were going through JPEGmini Pro then, they were still at 3000x2000 or something similar, pixel wise. When I reduced them to fit within a 1600x1600 square, that’s when the blurry preview bug was fixed