I was going to say, an LCD (or other computer/TV) display screen is the classic example of where colours in close proximity (RGB sub-pixels) are perceived as the compound colour.

Basically I second kilotesla's answer, but will add some additional clarification and related ideas.

The "resolution" of the human eye is highest in the very central few degrees of vision, the "fovea", which is populated with "cone" cells which are colour-sensitive. The rest of the visual field is mostly populated by rod cells, which are only brightness-sensitive - but are sensitive to lower light-levels. See https://www.cis.rit.edu/people/faculty/montag/vandplite/pages/chap_9/ch9p1.html#:~:text=Rods%20are%20responsible%20for%20vision,is%20populated%20exclusively%20by%20cones.

Empirically (presumably in the fovea) the human visual system has a higher "resolution" for brightness or "luminance" than for colour - this has been exploited for decades in the way analogue colour television or JPEG images are encoded - with the colour being coded ("sub-sampled") at a lower resolution than the brightness (to reduce the information), with little visual perceptual loss.

Empirically the black-and-white resolution of the eye is of the order of 300dpi at about 14 inches for someone with good vision who can focus properly, in high-ambient light levels. You could probably find a reference to the definition of "20/20 vision" and get a comparable angle subtended. In very low light levels, the effective resolving power will be lower.

Combining those two observations, I would expect the colour resolution to be something like 80-150dpi at 14 inches. This is equivalent to a subtended angle of around 1/(100*14) radians, so (180/pi)/(100*14) = 0.04 degrees, give or take.

If the coloured lines or stripes are closer than that sort of subtended angle, the colours are likely to merge into one - they will not be "resolved". The merging will work a bit better where the pattern is alternating (like in a TV or computer screen), rather than just a single source of each colour - in the latter case you may still perceive a coloured "fringe" on each side, even when you can't properly resolve the two colours.

In the early days of LCD computer screens, in the early 2000's, when they were only 1024x768 resolution, and before the days of sub-pixel font rendering, if you had white text on a black background, where the letters were only 1 pixel wide, the text often appeared to have some chromatic aberration, an orange-tinge on the left of the letters and a bluey tinge on the right, just because of the subpixel layout. As displays became higher resolution, and font often rendered more than 1 pixel wide, and/or they used more-clever sub-pixel rendering techniques (such as Microsoft's ClearType) these effects largely became consigned to history.
See also https://en.wikipedia.org/wiki/Subpixel_rendering#:~:text=Subpixel%20rendering%20is%20a%20way,the%20screen%20type's%20physical%20properties.

Don't take my word for it... you could print a piece of paper with fine alternating black and white lines and establish at what distance the lines cease to be resolved and "go shimmery" and then merge into grey - to get a gauge of your own personal black and white resolution.
If you can find an old Trinitron cathode-ray tube (this uses RGB lines of phosphor) - which is lower resolution than modern displays, you could try the same thing - look closely, then move back until the colours merge. If you can determine the pitch of the stripes and the distance, you can work out the subtended-angle when the colours merge.

Perhaps more easily, you could create a graphic of red/green/blue stripes on your computer (make each line several pixels wide) then see how far away you need to be for the lines to merge and it looks white.

The results are likely to be slightly different (fuse at a slightly closer distance) if you match the luminance of the coloured stripes (have blue at full brightness, red somewhat less, and green lower still), making probably a bluey-lilac colour when merged.

If you do some Google searches (other search engines are available) relating to measuring the resolving power of optical systems, contrast ratio etc, this will get you a sense of the underlying physics, which is then largely applicable to the eye - for the purposes of the question.

(I'm a physicist/electronics engineer, who has also spent several years of my professional life in optics, imaging systems, colour-reproduction and display-screen technology.)