My original question above was a bit naive as I had not properly understood group message dynamics. The group incoming email/post system works perfectly and essentially is exactly what I/we need simply in a Group instead of Category (there isn’t much difference there really).
New on-boarded support staff with access to the support group(s) have access to the historical ticket archive by simply going to /g/[thegroupname]/messages/inbox which is essentially a category topics list.
As a side note for those interested I set the pre-foward incoming email system (help@test.com) to auto-reply a canned “thank you for your question” type email. Then the email is sent to the email-receiver to create the post. This keeps the customers calm and not posting a second time and gives me a bit of time to work the ticket response.
best,
Walker