There's been years and years of debates around the topic whether or not should a frontend engineer care about knowing backend code of their application or being able to do some UX for it, whether a backend engineer should care about being able to work on the frontend and perform DevOps tasks for their team. We can continue this list of combinations for long.

There is an opinion that strict specialisation is the answer here. Not only I disagree, but I will gladly prove you that Fullstack is nearly always the answer, no matter the position (but maybe not the Fullstack you are now thinking of).

I'll do my best to prove this point with examples of possible situations, growth paths and such.