While I am extremely proud of this solution, I ultimately decided against it and settled on separating the bots as containerised services. Nevertheless, the solution here is still valid and useful for a variety of situations, and so I'm leaving this post up in the hopes that you or someone you know will find it useful.
For the better part of the past month or so, I've been rewriting the bot(s) which power the official Brackeys Community Discord server. This post isn't so much a guide, as it is a vent. A window into my process of dealing with the ever-growing enterprise-level codebase I've signed myself up for, and the hurdles I've faced. Enjoy.