I mean I quit the game last year for a similar reason. I saved up a lot of cp for when Apoc, iHulk and Yelena were in latests. I was so excited and then I pulled like 10 Yelena, 3 iHulks and 1 Apoc. All of that hard work of saving up cp and grinding a stupid amount of wins in a lot of pvp events only to get punched in the gut from RNG. And I had a similar pull rate to yours not too long ago when I think I only did like 6%. It sucks but then you’ll have times when the game is throwing 5s at you ever other pull, or it’ll feel like it anyway.
I decided to pull the trigger before the store ended to see if I could finish covering Dr. Strange and champ him. I spent 400 CP and pulled:
2 x Beta Ray Bill
2 x Kitty Pryde
2 x Dr. Strange
Beta & Kitty were more champ levels and Dr. Strange is now champed. I had to fight so hard to stop pulling as I felt like I was on a streak.