Good luck! I jumped from a super boring consultancy job to work at a startup doing backend work which I never have done before besides the odd Django personal

Good luck! I jumped from a super boring consultancy job to work at a startup doing backend work which I never have done before besides the odd Django personal project. My recommendation is to first take some time and learn the tech stack. Take a course on the language, get familiar with AWS or whatever the infrastructure is, etc. Second, once you start, try to just get everything up and running beginning to end. Hopefully you can contribute some updates to documentation right away this way! After that, try to deploy a change, talk to the other engineers about the design history and why things are built the way they were, etc etc. Have fun!