Your CTO doesn't sound great, and beyond a certain size company it's a red flag for the CTO to have shipped code to prod that they don't operate or support. But in small enough companies that is a common pattern when there aren't enough resources around. Can you build a workaround to the hardcoded stuff? Can you propose changes to the hardcoded stuff? In a small/medium sized company there may not be any spare resources and it's up to you to propose working solutions. I think many senior engineers in your shoes would focus on shipping something that works within the constraints set by the business/managers. If the CTO says "you can't change this module," I would say "ok, I can work around that, here are the tradeoffs for doing so (readability, maintainability, correctness, uptime, schedule, etc), is that ok with you?" The best solution for the business is not always the most technically optimal/perfect one. If the CTO is ok with the tradeoffs then you need to ship what they want. The ultimate red flag is a manager that imposes constraints on you but won't accept the tradeoffs - that's...ok, I'm doing as little as possible to avoid getting fired while also doing a max effort job search.