Let me clarify that the Fog Glow implementation in the Realtime Compositor is essentially a higher quality and more temporally stable version of the Bloom implementation in EEVEE. This is more of an artistic effect than a realistic approximation of eye or camera response to highlights.
On the other hand, the Fog Glow implementation in the CPU Compositor is a not-so-good approximation of the response of the eye or camera to highlights, implemented by convolving the image with a specific point spread function, which in layman terms means we spread the highlights into neighbouring regions in a specific way described by this function. This roughly takes the shape of an exponential function, that’s why I proposed you approximate it using an exponential curve as you demonstrated in your image.
So your assessment is correct, final renders should have the RGB Curves node muted, since it already takes an exponential form. Though don’t expect the workaround to work nicely in all cases, since trying to adjust the point spread function by adjusting its result is fragile.