I'd also lean toward "no, we don't need an implementation-specific version of [all general technology tags / the entity-component-system tag in particular]" for the reasons Alexandre Vaillancourt described in this answer, as well as another specific to the ECS case:
I think the entity-component-system tag is good for unifying questions about ECS approaches or strategies, which can include applications to Unity without being limited to Unity specifics.
For instance, a user could ask "How can I adapt my AI search behaviour to work in a data-oriented ECS fashion?" with tags unity, entity-component-system data-oriented, etc. That question is high-level enough that anyone with experience thinking in an ECS way could help - suggesting what data to break out into components and what passes of systems/data transformations will achieve the same end. They don't necessarily need to know the ins and outs of Unity's job system to discuss the architecture at this level.
If we have questions that are very specific about Unity's implementation, say because they're about solving a problem in the HPC# language or making the Burst compiler behave a particular way, then I think those questions are better-served by identifying that focus more precisely - say having an
HPC#-Burst tag alongside c# to emphasize the distinction of this dialect. This calls out the specific skill set at hand rather than a general topic of interest.
I think a narrowly-focused tag like this is less likely to be misused as a catch-all for any and all questions relating to ECS approaches in Unity (served sufficiently by the existing unity entity-component-system tags), and better focuses on a specific area of expertise (ie. familiarity with a specific language/compiler), making it useful for searching/filtering.
Whether we need such an
HPC#-Burst tag at all remains to be seen. I haven't yet observed a large number of questions specific to the ins and outs of burst jobs in Unity, so for now I'd be inclined to watch & wait to see whether the topic develops into one that demands more filtering tools to navigate.