If anyone has a SDG2000X on hand would not mind checking the amplitude setting resolution at 1V and higher for sine - from the datasheet, it looks to be 4 digits only which means 1mV at 1V or higher. It would be delightful if it is at 0.1mV or better.
I'm afraid I am about to disappoint you. I just tested a little on my 2042X. 1V and above is just 1mV steps.
But it gets worse: I went just below 1V to get the 0.1mV steps, and the last digit doesn't do much good at all.
At a setting of 998.4 mV PP, I read (on a Fluke 187) an actual output of 352.59 mV RMS. With calibration age and so on, this is reasonable.
I then stepped up 0.1 mV to 998.5 mV PP, and the Fluke read 352.99 mV RMS. Now as I increased further, the Fluke didn't move at all. All the way from 998.5 to 999.6 mV PP (not a typo, the difference was 1.1 mV PP) and the output sat still at 352.99 mV RMS.
The next step to 999.7 mV PP made the Fluke jump to 353.39 mV RMS.
At much lower values (around 100 mV PP), the 0.1 mV digit did change the output at every step.