I have now played through the content couple of times while I think the content is fantastic (I really liked the diplomat and the leader backgrounds), but I though the speedrunner background felt a bit off-putting, maybe ill advised.
I don't think the Chris-chan reference wasn't appropriate for this and I think speedrunning stuff could be fascinating concept in this story. Not everything is bad, the just whatever signing of the contract with Argos was quite funny, however it can be improved.
What I know of speedrunning and its community is quite limited however we are talking about dedicated community of people playing a game that they generally enjoy and want to experience it in new ways. Breaking a game within rules of a game is somewhat a scientific effort, for example someone makes a hypothesis how this corner could be exploited, someone tries it out with an emulator with tools that helps to break it down frame by frame testing inputs to test if it is possible and someone else may come up with a way to roll to the corner to get out of bounds. I have listened how usually breaking down a game is a community effort. Usually what sparks interest in finding new skips or new routes is tedious or really hard sections.
I do think there is plenty fruitful ground to this in the visual novel that revolves around contracts and a magical world. A character with speedrunner a could have unique responses for trying to find unintended properties of stuff in magic or maybe find an exploit in the magic system of the world or find a loophole in contract.
I don't think it is my place really to say how you should write this or even if you want to edit the background at all. I just want to say I think there is untapped potential there.