The sneaky Jay plot works and you did a good job of painting the MC as the nerdy gamer outcast.
Some things to work on:
1. There's no hook at the beginning. I would start with the phone ringing. He wakes abruptly, Jump right into the conversation, grumbles at having to do chores before gaming
2. You spend a lot of time in chapter one building the Maria character and then you don't use her.
3. Needs some proofreading (bordering bothering).
4. What kind of game is it? Why is it popular? Why is he good at it? What's his specialty?
5. Got lost in the fight scene in chapter one (Does the assassin have a shadow ability? I couldn't figure it out)
6. I would add some foreshadowing at the end of chapter one