I’m glad to hear yours have been holding up! Maybe my friends and I were just particularly unlucky.
The service manuals are available direct from Dell. For all the laptop’s faults in my experience, I do appreciate that the SSDs are socketed, as are the RAM sticks on the 15. I do also appreciate that Dell sells replacement batteries (and they aren’t glued in either!) as that’s usually the first part to need a swap.
For real though, Gojo soap seems to work the best for getting rid of grease and oil from machines. My guess is regular soaps don’t do a great job at carrying away the oil residue, but Gojo soap just sands down your top skin layer to remove it.