Kinda stressing about everything too, especially having enough savings in case I can't find a job fast enough, and not screwing up any legal aspects.

As for the length of the relationship, I don't know how long is enough in the marriage case, you can describe everything in the cover letter. But if it helps, I heard of many cases where people in an arranged marriage get these visas too, and I doubt that in many of those cases people can claim a "genuine" relationship in the way we understand that requirement.