With the following code:
wiz.res("Wellenlänge", 5.4066e-7, 1.0297e-9, 3.6457e-9, r"\m")
will print to the console:
Wellenlaenge = (5.407 ± 0.010 (sys) ± 0.04 (stat))e-7 m
We end up with the following string in results.tex:
\qty{5.407 \pm 0.010\UncertSys \pm 0.04\UncertStat e-7}{\m}
This will show up in the document as

Note the additional 0 after the text "stat". The problem is that siunitx tries to show the same number of digits for systematic and statistical error, which I find a reasonable way of doing things.
With the following code:
will print to the console:
We end up with the following string in
results.tex:This will show up in the document as

Note the additional
0after the text "stat". The problem is thatsiunitxtries to show the same number of digits for systematic and statistical error, which I find a reasonable way of doing things.