AFAIK, image sensors use demosaicing algorithms to reconstruct virtual image pixel from different sub-pixels. Does it mean, that on some cameras it could be profitable to use lower-resolution modes to get better out-of-the-box picture?
I shoot show-jumping on Canon 80D indoors and not so good in using raw-therapee to get really good results from RAWs (and sometimes there are just bugs, ex. I see no difference when applying some noise reduction). And on JPEGs image is quite blurry on HighISO even on my FullHD monitor due to noise, so there is absolutely no sense in additional megapixels. With new 90D on the way and increased megapixel size it becomes even more actual.
So whether I will see better picture on my monitor using in-camera lower resolution compared to L-size JPEG that is converted to FullHD automatically by image viewer or by converters of social networks?