I've never seen so much technical debt in my 10+ year career as a software developer. This was by far the worst piece of software I ever worked with. The company has strong and isolated silos - dba team, architect team, UX team, and so on. No one communicates, and everything is a mess.
The main software is based on rails and has very old and completely deprecated gems. The entire application message pubsub is based on a gem that has been deprecated and discontinued 8 years ago, and when asking why that, that answer is: it's working fine, there is no need to touch it.
Management is toxic. I've never seen such a high employee turnover, and no one really wants to see how deep is the problem. Management seems to be brainwashed, everyone keeps saying "everything is fine, just keep going". CTO once said: "Yes we're losing a bunch of people, but we're also hiring new people. The number of employees is stable, so everything is fine!". This has been said to the whole company, in an all-hands meeting. Do I need to say more?