Why not use an app that does this kind of thing? I’ve never used it but it sounds like Habitica on iOS devices does something similar to game-ify your productivity. You have a bunch of tasks (quests). Complete each quest and gain experience points. Level up when you finished enough tasks.
I haven’t tried it myself but it sounded interesting. I don’t know if I would need a scoring system to reward myself. I just go to my Today perspective, finish off as many as I can and then reward myself.