Smooth stroke seems almost pointless at current
I think that the smooth stroke option in Gimp is currently either broken, or way too weak.
I run Gimp 2.10.4
Here is an example of two lines drawn in Gimp compared to MS paint, all lines are drawn at 100% zoom:
There isn't much difference between the smooth stroke settings being maxed out, or having it off.
It wouldn't be unreasonable to say that at max weight and at highest quality that any line drawn should be similar to a perfect semi circle in this case.
A solution would be to make the weight setting "infinite". (No reason for a hard stop at "1000.0")
Another thing would be to add "inertia" to the path, ie that the line will continue in its current direction for a while. (Not to be confused with weight (how much the drawing "lags behind" the pointer), or quality. (how often it makes the smoothing calculations for the path) Though, depends on how the smoothing is implemented, like if it is a simple boxcar average, or something else.)
(Another totally different "solution" (far more complicated, and requires far more work) would be to add proper vector tools to the program. There is the Paths tool, but it generally feels like a bodge, and tracks disappear if one clicks away to check that one's brush is set correctly. (Though, preferably we should go into the rabbit hole of non destructive editing, if we regard the vector path as a brush stroke that we later can change/edit and have it re-render the stroke accordingly. Then we should probably also have filter layers too...) (Obviously this is an overkill "fix" for the smooth stroke feature... And is generally more food for thought about how to improve the program overall, then a worth while fix for the smooth stroke feature.))