Does anybody know the screw specifications for the Dell Latitude 5490 for:

Back cover.  Type (known - flat) , screw diameter, length, thread / pitch.  Whoever worked on my refurb unit stripped the Philips "slot" on 2 of the screw heads of the black screws that secure the back cover.  These appear to be M2 x 7mm, pitch unknown.

Hold down screw for the NVMe M.2 SSD.  What is in there is a short flat head screw, but, it appears that a washer or pan head would be better.  The installed screw appears to be a Philips M2 x 4mm*, pitch unknown.
*Estimate -- I did not measure this one.

Hold down screw for the SATA M.2 SSD in the WWAN slot.  (Yeah, I got the drive to work.).  Nothing was installed in the WWAN slot as I received the machine, so, not surprisingly, no screw...  It appears that a washer or pan head screw would be best.  Best guess would be that it should be a Philips M2 x 4mm*, pitch unknown.
*Estimate -- Nothing there to measure.