I think it is absolutely baffling that you can filter by almost every field except tags… what is the point of tagging a task if you can’t use the tags…
Welcome, @Guy_Boggan,
I know this is frustrating, so not by way of excusing, just by way of explaining…
Tags was an original feature of Asana when it was released, I believe, around 13 years ago. Not too long later, Custom Fields were added. At some point Asana more or less stopped enhancing Tags, though they continued supporting their use. Then much later Filters were added. Asana has chosen to devote resources to other features. So I try to steer clients away from Tags except where they suffice, with no further expectations.
Sorry,
Larry