Win/loss Elo is unfair

Today alone i’ve played 8 games and went 4-4. In the 4 games that I won, I had a 79% chance (to win), an 83% chance, a 49% chance, and a 97% chance - all of which earned me 74 total elo (I play around 2600). In the following single game where my chances to win were 49%, I lost 75 elo while the lowest earner on the other team received 112. I then proceeded to play 3 games in a row where my chances to win were all less than 20%, and proceeded to lose a combined 80 more. Dont understand how after going even in wins and losses I can still have my elo be ruined, takes away alot from the purpose of just winning, why not just make it always 25 or 50 for wins or losses either way.