For big companies, MVC and microservices both are used depending on the needs. Along with microservices architecture comes cloud native development and cloud provider specific database solutions (usually for nosql). If you wanna learn the backend dev, follow the roadmap (https://roadmap.sh/backend).
A few tips:
Don't jump stacks. Stick with one.
It is okay to use javascript, java and even C++. There are jobs for each stack and programming language. Even cobol jobs exist.
Learn tests and CI/CD within your stack.
Get super good with databases and data in general. You can jump around backend dev and data engineering jobs easily.
Learn cloud native development.
Learn API standards. I have seen pretty ugly REST APIs in my experience with PHP. People seriously need to learn REST standards.
GraphQL, SOAP API are important too but you can get a job with REST only.
Learn hotwiring. Hotwire stands for html over the wire and it works by sending partial html elements using websocket or ajax and injecting it into DOM in real time. It is usually done with a library like hotwire (rails) or livewire (laravel) or similar library in your framework.
Python in my opinion is not mature enough for backend dev as it lacks a few libraries (for example fault tolerance is hard in python) and it is only being promoted as one solution for everything because academics love it. But you are free to pick whatever language/stack you like. There are many jobs for python devs these days. Almost same as java devs.