Winner of over 175 Game of the Year Awards and recipient of over 250 perfect scores, RDR2 is the epic tale of outlaw Arthur Morgan and the infamous Van der Linde gang, on the run across America at the dawn of the modern age. Also includes access to the shared living world of Red Dead Online.
IIRC you get an extra robbery mission, a hideout mission, an extra outfit and some more things like store discounts and stat bonuses.
The rest is Online mode bonuses like free weapons and outfits.
If you go for the regular edition I don’t think you’ll notice these “missing” things.