I don't have enough time play and take max profit of all game modes, so I would like to know what are the rewards I can get from salmon run (and an approximate idea of what takes to get them)
You can get Grizzco/Salmon Run exclusive clothes that you can't buy anywhere else, you can get badges to put on your clothes to increase stats, and you can get lots of gold. I spend about 2 hours playing Salmon Run and I get minimum 15000 gold, 2 different outfits, and 4 badges. Most of the time I make a little more gold than that but these are just estimates, I haven't actually counted.
EDIT: I forgot to mention tickets. You can get tickets from Salmon Run that you give to Crusty Sean and get stat bonuses like 2x gold/xp in battle, increased swimming speed, sub uses less ink, etc. all last for 20 online battles.