I find it to more about a thin line being rendered as a little bit of color in two adjacent lines of pixels. The result is a messy blur instead of a crisp line. If any layer of the libraries and APIs doesn’t pass up the coordinate system mappings, like say a window doesn’t report its exact screen space position to its content, then you lose access to the information to register the pixels precisely.
That can definitely happen between but as a loss of information between layers that don't support DPI fully (e.g. Windows 7 type DPI information which isn't per screen aware) or are intentionally ignoring physical pixel information (e.g. percentage based sized/positioned elements) not float precision loss. Float precision loss is definitely a thing but even a 32 bit float is integer perfect to 8,388,608 meanwhile a 7,640 pixel screen (1,000 times smaller) is considered extraordinarily large. Fractions close to 0 (such as APIs that use a 0-1 range for the screen or DPI represented a a percentage of a standard value) have a similar accuracy.
I'm not even sure on Windows there is a way to render anything
