Always a great topic that we think about often. Here’s one way to look at it that may be a middle-ground…

Specialize in solving a chunk of he design process, not a specific skill

This could be things like:

• specializing in the end game (getting design intent actually built) which would be focusing on relationships with engineers, focusing on front-end coding, etc
• Specialize in validating design (helping create lofi prototypes, research plans, presenting to stakeholders, etc)
• Specializing in setting direction (concepts, leadership reviews, strategy, setting road maps, etc.)

This helps you define value in part of a design process without locking yourself into too few skills.