Brains are complicated. Speaking about the more common deutan trichromancy (protan has a characteristic dimming of reds such that "same luminance" colors are visually different brightnesses), for me red and green are still separate and distinguishable parts of the spectrum, both again separate from the yellows and oranges. What happens is that red is not "visually obvious", in the sense that the sense that I register it subconsciously.

Here's an example photo I took in a tulip field with spots of emerging red flowers in a sea of green: https://i.imgur.com/44VRERI.jpeg

I can see the flowers if I look at them, but if I hold the picture in my peripheral vision away from my focal center, I don't register the spots of red in the back of the field.

What tends to happen with anamolous trichromats is that the brain compensates in a bunch of different ways. Lightness contrast sensitivity goes up, color contrast sensitivity goes up, and your brain "alters" the perceived colors closer to what a color normal person would perceive. The brain is mostly able to compensate for the reduced functionality to the point where you might not even know you're colorblind until you do color matching tests. This doesn't fix everything though, and this happens to be a common weakness for deutans.