Ability to exclude certain categories from Related Topics (Similar Topics)

I’m really appreciating the Related Topics feature here — it’s very good compared to the previous “Suggested Topics” list, and in fact actually useful.

However, there are a number of “workflow” categories we have which I would like excluded from the results. Would it be possible to have a config option with a list of categories? An include list would actually be better than an exclude list.

Even better: per-category configuration for other categories to include (with a default to "just this category).