After some digging in, I was able to debug the issue and work on a fix thanks to ChatGPT

Seriously, ChatGPT is a life saver, I'm not an ops person but I was able to use the tips it provided to diagnose the issue, and after learning a bit about GRUB and shit I was able to fix it properly.

I'll be paying more attention to kernel updates and implementing a new update procedure + adding another standby app server to prevent this in the future.

Running prod services are fun, until they aren't