That sounds rough. It's very painful not having time to do things properly, and it's also painful when you don't have proper requirements so you can't even be totally sure what properly even is. I semi-recently left a job (the one I was talking about originally) after more than once being told "we just want a toy, proof of concept version and any time you spend on things like performance is a waste of time and we will scold you for it, even if there isn't any other work for you to do" before they decided to ship my "toy proof of concept" to a client requiring an ungodly rework of it while it was running in a production environment.

I honestly think people denigrate having at least some actual design work and requirements done upfront as being "too waterfall" and think doing it is a bad idea so we as an industry end up with not even the intentions of how a piece of code should work written down and no idea how stuff works once the original author moves on