Hi,
I'm a B.Tech 2019 passout in ECE from one of the NIT(-_-), working in one of the top service based companies as a Data Engineer. I want to shift to a Product based company and learn stuff making a career here albeit in a entry role. I can handle python language well and started practicing DS and Algos too.
Can the community kindly suggest on

1. The resources I can rely on.
2. How to approach System Design concepts
3. Is Python language enough to crack product based companies (or C++ is a must?)
4. If there is any roadmap or consolidated resources
5. *** How to approach Product based companies once prep is done ***

I heard lots of stories regarding people moving from service - product after 2-3 yoe. If any such person views this post, kindly share your grind too.

Thanks in advance.