Sugguestion to help Negative Attitude
Add in an program like AFK tracking program that tracks people who spam the surrender button. People who spam it a lot give them a warning. If they continue to do it then follow up with further punishment.
Also make it so in ranked if you click "yes" to surrender than you will lose extra LP. Make it so surrendering is a last resort so people will actually try their hardest in ranked instead of just giving up so easily.
Make a BIG announcement of it and talk about how you want players to try their best in a game to inspire players but to give people a bit more thought before surrendering. This would help fix A LOT of negative attitude in games I believe.