I would also avoid preparing for the role directly but prepare for software "in general".
You can learn a stack but still not have a great grasp of how MVC actually works and how the framework interacts with the database.
Instead of going over algorithms or frameworks, I would make sure you understand basic data structures and databases. You're going to be working with these no matter where you go.
For data structures, I would focus on hash maps and queues; you'll likely be using those much more than anything else. I would make sure to have a solid foundation in SQL queries because then you'll know what the framework's ORM is doing. Also you mentioned working on backend, so SQL should be your bread and butter (you need to know to avoid N+1 queries, etc).
I've gotten many interviews and at least one job based primarily (after being a nice person to work with, anyway) on having a good foundation in SQL; I wrote a toy ORM and put it on github.
You can learn a stack but still not have a great grasp of how MVC actually works and how the framework interacts with the database.
Instead of going over algorithms or frameworks, I would make sure you understand basic data structures and databases. You're going to be working with these no matter where you go.
For data structures, I would focus on hash maps and queues; you'll likely be using those much more than anything else. I would make sure to have a solid foundation in SQL queries because then you'll know what the framework's ORM is doing. Also you mentioned working on backend, so SQL should be your bread and butter (you need to know to avoid N+1 queries, etc).
I've gotten many interviews and at least one job based primarily (after being a nice person to work with, anyway) on having a good foundation in SQL; I wrote a toy ORM and put it on github.