From super senior dev perspective. You're not going to be there for the rest of your life. One year is enough. Take it easy. I went through this multiple times

From super senior dev perspective. You're not going to be there for the rest of your life. One year is enough. Take it easy. I went through this multiple times, there are lots of places with a shitty code. The worst thing that can happen - you'll will start blaming yourself. But if you just relax and let things go, you'll get salary, 9 to 5, job security. Don't try to fix everything in one day. File stories, fix issues one by one. Eventually you will like it, and this is the real software engineering, the real world. Yes, there are better places, but you will never know until you get there. So if you can live with it for about a year, it's good. If not, start looking, and remember - it's not your fault, and it's very hard to avoid that. You need to work in a company for a couple of weeks to understand how things are going there. So you new job can be the same or even worse (it also can be better). But there are no any guarantees.