The way it’s presented is a little confusing, and at the very least the modified date could include the time as well.
The auto saved files, which then become your Recovered files in the Welcome window, are in this folder:
~/Library/Application Support/SketchUp 2019/working/SKETCHUP/RecoveredFiles/
You can do a test where you have set auto save to 1 minute, then watch that folder as you work on a currently saved file. Don’t do any changes, and no auto save file will appear. Do a change but don’t save, and within a minute an auto save file will appear. Do a save now, and the auto save file is removed.
In theory, the only time there is an auto save file is when you have made changes, and it’s more time since your auto save setting since you last saved.
If you Force Quit at that point, and open SketchUp again, you’ll now see the Recovered file in your recent files area. That thumbnail seems to represent both the last saved version and the recovered version, so you’re asked which of the two you want to open. Looking at the thumbnails is a good idea. If you choose the last saved version, you’re given a warning that opening that one will delete the recovered file, and that if you really wanted the recovered file, to cancel, open the recovered file, and save as a new name.
If all of that wasn’t complicated enough, if you choose to open the file from File/Recent, you are just shown a dialog box with no thumbnails, and whatever you decide to do is instant.
So, in general, if you had a crash and you see Recovered as part of your recent file name in the Welcome window, choose that, and when asked if you mean it, look at the thumbnails to see if the things you had done since the last save are worth keeping. Think about that too, because it could be that the last thing you did is what is crashing SketchUp.
One advantage of saving the recovered file as a new name file is that you do still have the previously saved file, and you can then take your time comparing the two, to see what was changed between the last save and the the most recent auto save before the crash.