If you want to try the power supply thing, go ahead. Understand there is a component that receives power from either source, so if that component is bugged, then it won't matter which source it's getting power from.
The drive stuff looks all clean, but I would not sit the drive out of this cuz of that. I still suspect the drive is somehow dying, and if it dies at sudden moments, SMART will not record the event nor drive tests will show up anything.
Here are the software that usually affect this kind of thing that could be suspect causes, beyond what drivers you've already updated:
1. Antivirus software
2. File/Drive Encryption software
3. Virtual drive (e.g Daemon Tools) software
4. File/Directory Utility software
5. Cloud Storage software (e.g. Dropbox)
Update - and in some cases cleanup and uninstall - all of those that may be present on your system, especially the A/V.
Also, I'm pretty confident re-seating your hard drive will not void your warranty. It is one of the few items in a laptop that's designed to be easily accessible and replaceable. Still, if you are unsure, consult your warranty on it before attempting to re-seat the hard drive. As for the actual process, it's very simple. Typically there's a plate on the back of the laptop that you unscrew to reveal the drive, then you unscrew and slip the drive out then back in and screw back in.
Since you are under warranty, you may wanna bring it in for servicing or replacement by your OEM.