1) Tomato, maybe we should move this to the PRODUCTS Forum. I was told that's where this sort of ting belongs.
2) I agree with your suggestion and yes top DMMs do, I looked long and hard for one that self-calibrated to a known good internal standard, and found the HP-34470A, it one-button autocals in 15 seconds. Manual calibration of old DMMs takes a long time, requires tons of calibration gear, charts etc.(like my HP-3478A- totally beyond my skill-set).
The Keysight 34470A was a good investment for me.
Geo