I use a single deck, which seems to be a commonly accepted best practice for Anki because mixing topics is good for learning.

I do tag my cards. For example, if a card is "In HTML, what header should you use to make a website responsive?", I would tag it with "programming," "webdev," and "html." The organization is there, but I haven't actually found a use case for the tags yet.

My plan is to use tags for deleting cards. For example, when I take another job/role then lots of cards should become obsolete.