I think is this one: https://www.mangago.zone/read-manga/wortenia_senki/
The one I know that fits that description is https://www.mangago.zone/read-manga/wortenia_senki/
I have read all chapters on this site. It was odd he got his revenge so early in the story, normally the MC's have to wait for a long time for their revenge. The way it is written, seems like the story can go further, so I guess it's a waiting game at this point. I would like to see him get revenge on his bully classmates eventually.
For once I wish the group straight up kills their summoner when it's an evil one. I know this one manga where the guy did do that, but he just killed the summoner and not the government who literally enslave people they summon. It would be so satisfying