There's been years of debate around the topic whether or not should a frontend engineer care to know backend code or be able to UX bits for it, whether a backend engineer should care about being able to work on the frontend and do DevOps for their team. The list of combinations is long.
There is an opinion that strict specialisation is the answer. Not only I disagree, but I want to prove you that Fullstack is nearly always the answer (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.